L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.8.x
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This module provides
conceptual and configuration information for point-to-point Layer 2 (L2)
connectivity.
These point-to-point
services are supported:
Local Switching—A
point-to-point circuit internal to a single
Cisco ASR 9000 Series Router, also
known as local connect.
Pseudowires—A
virtual point-to-point circuit from a
Cisco ASR 9000 Series Router.
Pseudowires are implemented over MPLS.
Note
Point to Point
Layer 2 Services are also called as MPLS Layer 2 VPNs.
Note
For more information about Point to Point Layer 2 Services on the Cisco ASR 9000 Series Router and for descriptions of the commands listed in this module, see the “Related Documents” section.
Feature
History for Implementing Point to Point Layer 2 Services
Release
Modification
Release
3.7.2
This feature was introduced.
Release
3.9.0
Scale enhancements were introduced.
Release
4.0.0
Support
was added for Any Transport over MPLS (AToM) features.
Release
4.0.1
Support
was added for these features:
Pseudowire Load Balancing
Any
Transport over MPLS (AToM) features:
HDLC over MPLS (HDLCoMPLS)
PPP over MPLS (PPPoMPLS)
Release
4.1.0
Support
was added for the Flexible Router ID feature.
Release
4.2.0
Support
was added for these features:
MPLS
Transport Profile
Circuit EMulation (CEM) over Packet
Release
4.3.0
Support
was added for the L2VPN Nonstop Routing feature.
Release
4.3.1
Support
was added for these features:
L2TPv3 over IPv6 Tunnel
ATMoMPLS Cell Relay VP Mode
GTP
Load Balancing
Release
5.1.0
Support
was added for these features:
Two-way pseudowire (PW) for ATM/CEMoMPLS
PW
grouping for Multi-Segment PW
Hot
Standby PW for ATM/CEMoMPLS
MR-APS Integration with Hot-Standby PW
Release
5.1.2
Support
was added for the following:
Dynamic Single Segment Pseudowire.
Faster network convergence after pseudowire failure.
Prerequisites for
Implementing Point to Point Layer 2 Services
You must be in a
user group associated with a task group that includes the proper task IDs. The
command reference guides include the task IDs required for each command.
If you suspect user
group assignment is preventing you from using a command, contact your AAA
administrator for assistance.
Information About
Implementing Point to Point Layer 2 Services
To implement Point to
Point Layer 2 Services, you should understand these concepts:
Layer 2 Virtual
Private Network Overview
Layer 2 Virtual Private Network (L2VPN) emulates the behavior of a LAN
across an L2 switched, IP or MPLS-enabled IP network, allowing Ethernet devices
to communicate with each other as they would when connected to a common LAN
segment. Point-to-point L2 connections are vital when creating L2VPNs.
As Internet service providers (ISPs) look to replace their Frame Relay
or Asynchronous Transfer Mode (ATM) infrastructures with an IP infrastructure,
there is a need to provide standard methods of using an L2 switched, IP or
MPLS-enabled IP infrastructure. These methods provide a serviceable L2
interface to customers; specifically, to provide virtual circuits between pairs
of customer sites.
Building a L2VPN system requires coordination between the ISP and the
customer. The ISP provides L2 connectivity; the customer builds a network using
data link resources obtained from the ISP. In an L2VPN service, the ISP does
not require information about a the customer's network topology, policies,
routing information, point-to-point links, or network point-to-point links from
other ISPs.
The ISP requires provider edge (PE) routers with these capabilities:
Encapsulation of L2 protocol data
units (PDU) into Layer 3 (L3) packets.
Interconnection of any-to-any L2 transports.
Emulation of L2 quality-of-service (QoS) over a packet switch
network.
Ease of configuration of the L2 service.
Support for different types of tunneling mechanisms (MPLS, L2TPv3,
IPSec, GRE, and others).
L2VPN process databases include all information related to circuits
and their connections.
Layer 2 Local
Switching Overview
Local switching
allows you to switch L2 data between two interfaces of the same type, (for
example, Ethernet to Ethernet) and on the same router. The interfaces can be on
the same line card, or on two different line cards. During these types of
switching, Layer 2 address is used instead of the Layer 3 address. A local
switching connection switches L2 traffic from one attachment circuit (AC) to
the other. The two ports configured in a local switching connection are ACs
with respect to that local connection. A local switching connection works like
a bridge domain that has only two bridge ports; traffic enters one port of the
local connection and leaves the other. However, because there is no bridging
involved in a local connection, there is neither MAC learning nor flooding.
Also, the ACs in a local connection are not in the UP state if the interface
state is DOWN. (This behavior is also different when compared to that of a
bridge domain.)
Local switching ACs
utilize a full variety of L2 interfaces, including L2 trunk (main) interfaces,
bundle interfaces, and EFPs.
Additionally,
same-port local switching allows you to switch Layer 2 data between two
circuits on the same interface.
ATMoMPLS with L2VPN
Overview
ATMoMPLS is a type of Layer 2
point-to-point connection over an MPLS core.
To implement the
ATMoMPLS feature, the
Cisco ASR 9000 Series Router
plays the role of provider edge (PE) router at the edge of a provider network
in which customer edge (CE) devices are connected to the
Cisco ASR 9000 Series Router.
Virtual Circuit
Connection Verification on L2VPN
Virtual Circuit
Connection Verification (VCCV) is an L2VPN Operations, Administration, and
Maintenance (OAM) feature that allows network operators to run IP-based
provider edge-to-provider edge (PE-to-PE) keepalive protocol across a specified
pseudowire to ensure that the pseudowire data path forwarding does not contain
any faults. The disposition PE receives VCCV packets on a control channel,
which is associated with the specified pseudowire. The control channel type and
connectivity verification type, which are used for VCCV, are negotiated when
the pseudowire is established between the PEs for each direction.
Two types of packets
can arrive at the disposition egress:
Type 1—Specifies
normal Ethernet-over-MPLS (EoMPLS) data packets.
Type 2—Specifies
VCCV packets.
Cisco ASR 9000 Series Router
supports Label Switched Path (LSP) VCCV Type 1, which uses an inband control
word if enabled during signaling. The VCCV echo reply is sent as IPv4 that is
the reply mode in IPv4. The reply is forwarded as IP, MPLS, or a combination of
both.
VCCV pings counters
that are counted in MPLS forwarding on the egress side. However, on the ingress
side, they are sourced by the route processor and do not count as MPLS
forwarding counters.
Ethernet over MPLS
Ethernet-over-MPLS
(EoMPLS) provides a tunneling mechanism for Ethernet traffic through an
MPLS-enabled L3 core and encapsulates Ethernet protocol data units (PDUs)
inside MPLS packets (using label stacking) to forward them across the MPLS
network.
EoMPLS features are
described in these subsections:
Ethernet Port
Mode
In Ethernet port mode,
both ends of a pseudowire are connected to Ethernet ports. In this mode, the
port is tunneled over the pseudowire or, using local switching (also known as
an
attachment
circuit-to-attachment circuit cross-connect) switches packets or frames
from one attachment circuit (AC) to another AC attached to the same PE node.
The following figure
provides an example of Ethernet port mode.
Figure 1. Ethernet Port
Mode Packet Flow
VLAN Mode
In VLAN mode, each
VLAN on a customer-end to provider-end link can be configured as a separate
L2VPN connection using virtual connection (VC) type 4 or VC type 5.
VC type 5 is the default mode.
As illustrated in the
following figure, the Ethernet PE associates an internal VLAN-tag to the
Ethernet port for switching the traffic internally from the ingress port to the
pseudowire; however, before moving traffic into the pseudowire, it removes the
internal VLAN tag.
Figure 2. VLAN Mode Packet
Flow
At the egress VLAN PE,
the PE associates a VLAN tag to the frames coming off of the pseudowire and
after switching the traffic internally, it sends out the traffic on an Ethernet
trunk port.
Note
Because the port is
in trunk mode, the VLAN PE doesn't remove the VLAN tag and forwards the frames
through the port with the added tag.
Inter-AS
Mode
Inter-AS is a
peer-to-peer type model that allows extension of VPNs through multiple provider
or multi-domain networks. This lets service providers peer up with one another
to offer end-to-end VPN connectivity over extended geographical locations.
EoMPLS support can
assume a single AS topology where the pseudowire connecting the PE routers at
the two ends of the point-to-point EoMPLS cross-connects resides in the same
autonomous system; or multiple AS topologies in which PE routers can reside on
two different ASs using iBGP and eBGP peering.
The following figure
illustrates MPLS over Inter-AS with a basic double AS topology with iBGP/LDP in
each AS.
Figure 3. EoMPLS over
Inter-AS: Basic Double AS Topology
QinQ Mode
QinQ is an extension
of 802.1Q for specifying multiple 802.1Q tags (IEEE 802.1QinQ VLAN Tag
stacking). Layer 3 VPN service termination and L2VPN service transport are
enabled over QinQ sub-interfaces.
The
Cisco ASR 9000 Series Routers implement the Layer 2 tunneling or
Layer 3 forwarding depending on the subinterface configuration at provider edge
routers. This function only supports up to two QinQ tags on the SPA and fixed
PLIM:
Layer 2 QinQ VLANs
in L2VPN attachment circuit: QinQ L2VPN attachment circuits are configured
under the Layer 2 transport subinterfaces for point-to-point EoMPLS based
cross-connects using
both
virtual circuit type 4
and
type 5
pseudowires and point-to-point local-switching-based
cross-connects including full interworking support of QinQ with 802.1q VLANs
and port mode.
Layer 3 QinQ
VLANs: Used as a Layer 3 termination point, both VLANs are removed at the
ingress provider edge and added back at the remote provider edge as the frame
is forwarded.
Layer 3 services over
QinQ include:
IPv4 unicast and
multicast
IPv6 unicast and
multicast
MPLS
Connectionless
Network Service (CLNS) for use by Intermediate System-to-Intermediate System
(IS-IS) Protocol
In QinQ mode, each CE
VLAN is carried into an SP VLAN. QinQ mode should use VC type 5, but VC type 4
is also supported. On each Ethernet PE, you must configure both the inner (CE
VLAN) and outer (SP VLAN).
The following figure
illustrates QinQ using VC type 4.
Figure 4. EoMPLS over QinQ
Mode
QinAny Mode
In the QinAny mode, the service provider VLAN tag is configured on both
the ingress and the egress nodes of the provider edge VLAN. QinAny mode is
similar to QinQ mode using a Type 5 VC, except that the customer edge VLAN tag
is carried in the packet over the pseudowire, as the customer edge VLAN tag is
unknown.
Quality of
Service
Using L2VPN
technology, you can assign a quality of service (QoS) level to both Port and
VLAN modes of operation.
L2VPN technology
requires that QoS functionality on PE routers be strictly L2-payload-based on
the edge-facing interfaces (also know as
attachment circuits). The following figure illustrates L2 and L3
QoS service policies in a typical L2VPN network.
Figure 5. L2VPN QoS
Feature Application
The following figure
shows four packet processing paths within a provider edge device where a QoS
service policy can be attached. In an L2VPN network, packets are received and
transmitted on the edge-facing interfaces as L2 packets and transported on the
core-facing interfaces as MPLS (EoMPLS).
Figure 6. L2VPN QoS
Reference Model
High
Availability
L2VPN uses control
planes in both route processors and line cards, as well as forwarding plane
elements in the line cards.
The availability of
L2VPN meets these requirements:
A control plane
failure in either the route processor or the line card will not affect the
circuit forwarding path.
The router
processor control plane supports failover without affecting the line card
control and forwarding planes.
L2VPN integrates
with existing Label Distribution Protocol (LDP) graceful restart mechanism.
Preferred Tunnel
Path
Preferred tunnel path
functionality lets you map pseudowires to specific traffic-engineering tunnels.
Attachment circuits are cross-connected to specific MPLS traffic engineering
tunnel interfaces instead of remote PE router IP addresses (reachable using IGP
or LDP). Using preferred tunnel path, it is always assumed that the traffic
engineering tunnel that transports the L2 traffic runs between the two PE
routers (that is, its head starts at the imposition PE router and its tail
terminates on the disposition PE router).
Note
Currently,
preferred tunnel path configuration applies only to MPLS encapsulation.
Multisegment
Pseudowire
Pseudowires transport
Layer 2 protocol data units (PDUs) across a public switched network (PSN). A
multisegment pseudowire is a static or dynamically configured set of two or
more contiguous pseudowire segments. These segments act as a single pseudowire,
allowing you to:
Manage the
end-to-end service by separating administrative or provisioning domains.
Keep IP addresses
of provider edge (PE) nodes private across interautonomous system (inter-AS)
boundaries. Use IP address of autonomous system boundary routers (ASBRs) and
treat them as pseudowire aggregation routers. The ASBRs join the pseudowires of
the two domains.
A multisegment
pseudowire can span either an inter-AS boundary or two multiprotocol label
switching (MPLS) networks.
Figure 7. Multisegment Pseudowire: Example
A pseudowire is a
tunnel between two PE nodes. There are two types of PE nodes:
A Switching PE
(S-PE) node
Terminates PSN
tunnels of the preceding and succeeding pseudowire segments in a multisegment
pseudowire.
Switches
control and data planes of the preceding and succeeding pseudowire segments of
the multisegment pseudowire.
A Terminating PE
(T-PE) node
Located at
both the first and last segments of a multisegment pseudowire.
Where
customer-facing attachment circuits (ACs) are bound to a pseudowire forwarder.
Note
Every end of a multisegment pseudowire must terminate at a T-PE.
A multisegment pseudowire is used in two general cases when:
It is not possible to establish a PW control channel between the
source and destination PE nodes.
For the PW control channel to be established, the remote PE node
must be accessible. Sometimes, the local PE node may not be able to access the
remote node due to topology, operational, or security constraints.
A multisegment pseudowire dynamically builds two discrete pseudowire
segments and performs a pseudowire switching to establish a PW control channel
between the source and destination PE nodes.
Pseudowire Edge To Edge Emulation (PWE3) signaling and encapsulation
protocols are different.
The PE nodes are connected to networks employing different PW
signaling and encapsulation protocols. Sometimes, it is not possible to use a
single segment PW.
A multisegment pseudowire, with the appropriate interworking
performed at the PW switching points, enables PW connectivity between the PE
nodes in the network.
Pseudowire
Redundancy
Pseudowire redundancy
allows you to configure your network to detect a failure in the network and
reroute the Layer 2 service to another endpoint that can continue to provide
service. This feature provides the ability to recover from a failure of either
the remote provider edge (PE) router or the link between the PE and customer
edge (CE) routers.
L2VPNs can provide
pseudowire resiliency through their routing protocols. When connectivity
between end-to-end PE routers fails, an alternative path to the directed LDP
session and the user data takes over. However, there are some parts of the
network in which this rerouting mechanism does not protect against
interruptions in service.
Pseudowire redundancy
enables you to set up backup pseudowires. You can configure the network with
redundant pseudowires and redundant network elements.
Prior to the failure
of the primary pseudowire, the ability to switch traffic to the backup
pseudowire is used to handle a planned pseudowire outage, such as router
maintenance.
Note
Pseudowire redundancy is
provided only for point-to-point Virtual Private Wire Service (VPWS)
pseudowires.
Pseudowire Load
Balancing
To maximize networks
while maintaining redundancy typically requires traffic load balancing over
multiple links. To achieve better and more uniformed distribution, load
balancing on the traffic flows that are part of the provisioned pipes is
desirable. Load balancing can be flow based according to the IP addresses, Mac
addresses, or a combination of those. Load balancing can be flow based
according to source or destination IP addresses, or source or destination MAC
addresses. Traffic falls back to default flow based MAC addresses if the IP
header cannot proceed or IPv6 is be flow based.
This feature applies
to pseudowires under L2VPN; this includes VPWS and VPLS.
Note
Enabling virtual
circuit (VC) label based load balancing for a pseudowire class overrides global
flow based load balancing under L2VPN.
L2 Traffic
Tunneling with IP Load Balance Hashing for MPLS Encapsulated Packets
If the frame is
IP-based, the load-balancing flow “src-dst-ip” configuration causes the Layer 2
interfaces to use the IP header for flow balancing hash calculation. If the
frame is not IP-based, the MAC header is used for the hash calculation. In
previous releases, for an MPLS header between the MAC and IP headers, the code
would use the MAC header for the flow balancing hash.
From Release 6.4.1
onwards, the code analyzes the MPLS header, and if an IP header is available,
it uses that for hash calculation.
If the MPLS label
stack is more than four labels deep, the code stops looking for an IP header
and reverts to the MAC header hash calculation.
When L2VPN flow-based src-dst-ip load-balancing is configured, and if a payload with encapsulated GTP is used, the GTP ID
is considered for load-balancing criteria. Starting from Release 6.5.1, you do not have to configure the cef load-balancing command to use GTP ID as a criteria for load-balancing for L2VPN scenarios. However, you must explicitly configure CEF load-balancing
for Layer 3 scenarios.
Pseudowire
Grouping
When pseudowires (PWs)
are established, each PW is assigned a group ID that is common for all PWs
created on the same physical port. When a physical port becomes non-functional
or disabled, Automatic Protection Switching (APS) signals the peer router to
get activated and L2VPN sends a single message to advertise the status change
of all PWs that have the Group ID associated with the physical port. A single
L2VPN signal thus avoids a lot of processing and loss in reactivity.
For CEM interfaces, various levels of configuration are
permitted for the parent controllers, such as T1 and T3, framed or unframed. To
achieve best grouping, the physical controller handle is used as the group ID.
Note
Pseudowire grouping
is disabled by default.
Ethernet Wire
Service
An Ethernet Wire
Service is a service that emulates a point-to-point Ethernet segment. This is
similar to Ethernet private line (EPL), a Layer 1 point-to-point service,
except the provider edge operates at Layer 2 and typically runs over a Layer 2
network. The EWS encapsulates all frames that are received on a particular UNI
and transports these frames to a single-egress UNI without reference to the
contents contained within the frame. The operation of this service means that
an EWS can be used with VLAN-tagged frames. The VLAN tags are transparent to
the EWS (bridge protocol data units [BPDUs])—with some exceptions. These
exceptions include IEEE 802.1x, IEEE 802.2ad, and IEEE 802.3x, because these
frames have local significance and it benefits both the customer and the
Service Provider to terminate them locally.
Since the service provider simply accepts frames on an interface and
transmits these without reference to the actual frame (other than verifying
that the format and length are legal for the particular interface) the EWS is
indifferent to VLAN tags that may be present within the customer Ethernet
frames.
EWS subscribes to the concept of all-to-one bundling. That is, an EWS
maps a port on one end to a point-to-point circuit and to a port on another
end. EWS is a port-to-port service. Therefore, if a customer needs to connect a
switch or router to n switches or routers it will need n ports and n
pseudowires or logical circuits.
One important point to consider is that, although the EWS broadly
emulates an Ethernet Layer 1 connection, the service is provided across a
shared infrastructure, and therefore it is unlikely that the full interface
bandwidth will be, or needs to be, available at all times. EWS will typically
be a sub-line rate service, where many users share a circuit somewhere in their
transmission path. As a result, the cost will most likely be less than that of
EPL. Unlike a Layer 1 EPL, the SP will need to implement QoS and traffic
engineering to meet the specific objectives of a particular contract. However,
if the customer's application requires a true wire rate transparent service,
then an EPL service—delivered using optical transmission devices such as DWDM
(dense wavelength division multiplexing), CDWM (coarse wavelength division
multiplexing), or SONET/SDH—should be considered.
IGMP Snooping
IGMP snooping provides a way to constrain multicast traffic at Layer 2.
By snooping the IGMP membership reports sent by hosts in the bridge domain, the
IGMP snooping application can set up Layer 2 multicast forwarding tables to
deliver traffic only to ports with at least one interested member,
significantly reducing the volume of multicast traffic.
Configured at Layer 3, IGMP provides a means for hosts in an IPv4
multicast network to indicate which multicast traffic they are interested in
and for routers to control and limit the flow of multicast traffic in the
network (at Layer 3).
IGMP snooping uses the information in IGMP membership report messages to
build corresponding information in the forwarding tables to restrict IP
multicast traffic at Layer 2. The forwarding table entries are in the form
<Route, OIF List>, where:
Route is a <*, G> route or <S, G> route.
OIF List comprises all bridge ports that have sent IGMP membership
reports for the specified route plus all Multicast Router (mrouter) ports in
the bridge domain.
The IGMP snooping feature can provide these benefits to a multicast
network:
Basic IGMP snooping reduces bandwidth consumption by reducing
multicast traffic that would otherwise flood an entire VPLS bridge domain.
With optional configuration options, IGMP snooping can provide
security between bridge domains by filtering the IGMP reports received from
hosts on one bridge port and preventing leakage towards the hosts on other
bridge ports.
With optional configuration options, IGMP snooping can reduce the
traffic impact on upstream IP multicast routers by suppressing IGMP membership
reports (IGMPv2) or by acting as an IGMP proxy reporter (IGMPv3) to the
upstream IP multicast router.
Refer to the
Implementing Layer 2 Multicast with IGMP Snooping module in
the
Cisco ASR 9000 Series Aggregation Services Router Multicast
Configuration Guide for information on configuring IGMP snooping.
The applicable IGMP snooping commands are described in the
Cisco ASR 9000 Series Aggregation Services Router Multicast Command
Reference.
IP
Interworking
Customer deployments
require a solution to support AToM with disparate transport at network ends.
This solution must have the capability to translate transport on one customer
edge (CE) device to another transport, for example, Frame relay to Ethernet.
The Cisco ASR 9000 Series SPA Interface Processor-700 and the Cisco ASR 9000
Series Ethernet line cards enable the Cisco ASR 9000 Series Routers to support
multiple legacy services.
IP Interworking is a
solution for transporting Layer 2 traffic over an IP/MPLS backbone. It
accommodates many types of Layer 2 frames such as Ethernet and Frame Relay
using AToM tunnels. It encapsulates packets at the provider edge (PE) router,
transports them over the backbone to the PE router on the other side of the
cloud, removes the encapsulation, and transports them to the destination. The
transport layer can be Ethernet on one end and Frame relay on the other end. IP
interworking occurs between disparate endpoints of the AToM tunnels.
Note
Only routed
interworking is supported between Ethernet and Frame Relay based networks for
MPLS and Local-connect scenarios.
The following figure
shows the interoperability between an Ethernet attachment VC and a Frame Relay
attachment VC.
Figure 8. IP Interworking
over MPLS Core
An attachment circuit
(AC) is a physical or logical port or circuit that connects a CE device to a PE
device. A pseudowire (PW) is a bidirectional virtual connection (VC) connecting
two ACs. In an MPLS network, PWs are carried inside an LSP tunnel. The core
facing line card on the PE1 and PE2 could be a Cisco ASR 9000 Series SPA
Interface Processor-700 or a Cisco ASR 9000 Series Ethernet line card.
In the IP Interworking
mode, the Layer 2 (L2) header is removed from the packets received on an
ingress PE, and only the IP payload is transmitted to the egress PE. On the
egress PE, an L2 header is appended before the packet is transmitted out of the
egress port.
In Figure above , CE1
and CE2 could be a Frame Relay (FR) interface or a GigabitEthernet (GigE)
interface. Assuming CE1 is a FR and CE2 is either a GigE or dot1q, or QinQ. For
packets arriving from an Ethernet CE (CE2), ingress LC on the PE (PE2) facing
the CE removes L2 framing and forwards the packet to egress PE (PE1) using
IPoMPLS encapsulation over a pseudowire. The core facing line card on egress PE
removes the MPLS labels but preserves the control word and transmits it to the
egress line card facing FR CE (CE1). At the FR PE, after label disposition, the
Layer 3 (L3) packets are encapsulated over FR.
Similarly, IP packets
arriving from the FR CE are translated into IPoMPLS encapsulation over the
pseudowire. At the Ethernet PE side, after label disposition, the PE adds L2
Ethernet packet header back to the packet before transmitting it to the CE, as
the packets coming out from the core carry only the IP payload.
These modes support IP
Interworking on AToM:
Ethernet to Frame
Relay
Packets arriving
from the Ethernet CE device have MAC (port-mode, untagged, single, double tag),
IPv4 header and data. The Ethernet line card removes the L2 framing and then
forwards the L3 packet to the egress line card. The egress line card adds the
FR L2 header before transmitting it from the egress port.
Ethernet to
Ethernet
Both the CE
devices are Ethernet. Each ethernet interface can be port-mode, untagged,
single, or double tag, although this is not a typical scenario for IP
interworking.
AToM iMSG
This feature enables an interworking layer in the access network(s) to
terminate all non-Ethernet functionality and translate these connections to a
Ethernet centric service which can be terminated on the Layer 3 edge routers.
Currently, the time-division multiplexing (TDM) based services terminate on the
Layer 3 edge routers directly. A simplified and more cost optimized model for
the L3 networks is enabled by moving the TDM complexity into the access layer.
The Layer 2 encapsulation is removed from an IP packet by the ingress
PE’s attachment circuit facing ingress line card. The MPLS encapsulated IP
packet payload is then sent across the fabric to the core facing egress line
card. The egress line card then transmits the packet through the MPLS core. On
the remote PE, the MPLS label is removed, Layer 2 header of the egress AC is
added and finally the packet is sent to the connected CE. L2VPN VPWS has been
enhanced to support:
Point-to-Point Protocol (PPP)
High-level Data Link Control (HDLC)
Multilink Point-to-Point Protocol (MLPPP)
QOS support for all the encapsulation types
For more information on QoS, see the
Cisco ASR 9000 Series Aggregation Services Router Modular
Quality of Service Configuration.
The TDM ACs can be configured on these SPAs:
SPA-8XCHT1/E1
SPA-4XCT3/DS0
SPA-1XCHSTM1/OC3
SPA-2XCHOC12/DS0
SPA-1XCHOC48/DS3
SPA-4XT3/E3
SPA-4XOC3-POS-V2
SPA-8XOC3-POS
SPA-8XOC12-POS
SPA-1XOC48POS/RPR
SPA-2XOC48POS/RPR
Any Transport over
MPLS
Any Transport over
MPLS (AToM) transports Layer 2 packets over a Multiprotocol Label Switching
(MPLS) backbone. This enables service providers to connect customer sites with
existing Layer 2 networks by using a single, integrated, packet-based network
infrastructure. Using this feature, service providers can deliver Layer 2
connections over an MPLS backbone, instead of using separate networks.
AToM encapsulates
Layer 2 frames at the ingress PE router, and sends them to a corresponding PE
router at the other end of a pseudowire, which is a connection between the two
PE routers. The egress PE removes the encapsulation and sends out the Layer 2
frame.
The successful
transmission of the Layer 2 frames between PE routers is due to the
configuration of the PE routers. You set up a connection, called a
pseudowire,
between the routers. You specify this information on each PE router:
The type of Layer 2 data that
will be transported across the pseudowire, such as Ethernet and Frame Relay
The IP address
of the loopback interface of the peer PE router, which enables the PE routers
to communicate.
A unique
combination of peer PE IP address and VC ID that identifies the pseudowire.
Control Word
Processing
The control word
contains forward explicit congestion notification (FECN), backward explicit
congestion notification (BECN) and DE bits in case of frame relay connection.
Control word is
mandatory for:
Frame Relay
ATM AAL5
Frame Relay to
Ethernet bridged interworking
cHDLC/PPP IP
interworking
CEM (Circuit
Emulation)
The system does not map bits from
one transport end point to another across an AToM IP Interworking connection.
Whenever supported, control word is also
recommended for pseudowires, as it enables proper load balancing without packet
desequencing independent of L2VPN packet content. Without control word the
heuristics used to perform load balancing cannot achieve optimal results in all
cases.
High-level Data Link Control over MPLS
The attachment circuit (AC) is a main interface configured with HDLC
encapsulation. Packets to or from the AC are transported using an AToM
pseudowire (PW) of VC type 0x6 to or from the other provider edge (PE) router
over the MPLS core network.
With HDLC over MPLS, the entire HDLC packet is transported. The ingress
PE router removes only the HDLC flags and FCS bits.
PPP over MPLS
The attachment circuit (AC) is a main interface configured with PPP
encapsulation. Packets to or from the AC are transported through an AToM PW of
VC type 0x7 to or from the other provider edge (PE) routers over the MPLS core
network.
With PPP over MPLS, the ingress PE router removes the flags, address,
control field, and the FCS bits.
Frame Relay over
MPLS
Frame Relay over MPLS (FRoMPLS) provides leased line type of
connectivity between two Frame Relay islands. Frame Relay traffic is
transported over the MPLS network.
Note
The Data Link Connection Identifier (DLCI) DCLI-DLCI mode is
supported. A control word (required for DLCI-DLCI mode) is used to carry
additional control information.
When a Provider Edge (PE) router receives a Frame Relay protocol packet
from a subscriber site, it removes the Frame Relay header and Frame Check
Sequence (FCS) and appends the appropriate Virtual Circuit (VC) label. The
removed Backward Explicit Congestion Notification (BECN), Forward Explicit
Congestion Notification (FECN), Discard Eligible (DE) and Command/Response
(C/R) bits are (for DLCI-DLCI mode) sent separately using a control word.
MPLS Transport
Profile
MPLS transport profile
(MPLS-TP) tunnels provide the transport network service layer over which IP and
MPLS traffic traverse. Within the MPLS-TP environment, pseudowires (PWs) use
MPLS-TP tunnels as the transport mechanism. MPLS-TP tunnels help transition
from SONET/SDH TDM technologies to packet switching, to support services with
high bandwidth utilization and low cost. Transport networks are connection
oriented, statically provisioned, and have long-lived connections. Transport
networks usually avoid control protocols that change identifiers (like labels).
MPLS-TP tunnels provide this functionality through statically provisioned
bidirectional label switched paths (LSPs).
For more information
on configuring MPLS transport profile, refer to the
Cisco ASR 9000
Series Aggregation Services Router MPLS Configuration Guide.
MPLS-TP supports these
combinations of static and dynamic multisegment pseudowires:
Static-static
Static-dynamic
Dynamic-static
Dynamic-dynamic
MPLS-TP supports
one-to-one L2VPN pseudowire redundancy for these combinations of static and
dynamic pseudowires:
Static pseudowire
with a static backup pseudowire
Static pseudowire
with a dynamic backup pseudowire
Dynamic pseudowire
with a static backup pseudowire
Dynamic pseudowire
with a dynamic backup pseudowire
The existing TE
preferred path feature is used to pin down a PW to an MPLS-TP transport tunnel.
See
Configuring Preferred Tunnel
Path for more information on configuring preferred tunnel path. For a
dynamic pseudowire, PW status is exchanged through LDP whereas for static PW,
status is transported in PW OAM message. See
Configuring PW Status
OAM for more information on configuring PW status OAM. By default,
alarms are not generated when the state of a PW changes due to change in the
state of MPLS TP tunnel carrying that PW.
Circuit Emulation
Over Packet Switched Network
Circuit Emulation
over Packet (CEoP) is a method of carrying TDM circuits over packet switched
network. CEoP is similar to a physical connection. The goal of CEoP is to
replace leased lines and legacy TDM networks.
CEoP operates in two
major modes:
Unstructured
mode is called SAToP (Structure Agnostic TDM over Packet)
SAToP addresses
only structure-agnostic transport, i.e., unframed E1, T1, E3 and T3. It
segments all TDM services as bit streams and then encapsulates them for
transmission over a PW tunnel. This protocol can transparently transmit TDM
traffic data and synchronous timing information. SAToP completely disregards
any structure and provider edge routers (PEs) do not need to interpret the TDM
data or to participate in the TDM signaling. The protocol is a simple way for
transparent transmission of PDH bit-streams.
Structured mode
is named CESoPSN (Circuit Emulation Service over Packet Switched Network)
Compared with
SAToP, CESoPSN transmits emulated structured TDM signals. That is, it can
identify and process the frame structure and transmit signaling in TDM frames.
It may not transmit idle timeslot channels, but only extracts useful timeslots
of CE devices from the E1 traffic stream and then encapsulates them into PW
packets for transmission.CEoP SPAs are half-height (HH) Shared Port Adapters
(SPA) and the CEoP SPA family consists of 24xT1/E1, 2xT3/E3, and 1xOC3/STM1
unstructured and structured (NxDS0) quarter rate, half height SPAs.
Figure 9. Enterprise
Data Convergence using Circuit Emulation over Packet
The CEM
functionality is supported only on Engine 5 line cards having CEoP SPAs. CEM is
supported on:
CESoPSN and
SAToP can use MPLS, UDP/IP, and L2TPv3 as the underlying transport mechanism.
This release supports only MPLS transport mechanism.
CEoP SPA supports
these modes of operation:
Circuit
Emulation Mode (CEM)
ATM Mode
IMA Mode
Note
Only CEM mode is
supported.
Benefits of
Circuit Emulation over Packet Switched Network
CEM offers these
benefits to the service provider and end-users:
Saving cost in
installing equipment.
Saving cost in
network operations; as leased lines are expensive, limiting their usage to
access only mode saves significant costs.
Ensuring low
maintenance cost because only the core network needs to be maintained.
Utilizing the
core network resources more efficiently with packet switched network, while
keeping investment in access network intact.
Providing
cheaper services to the end-user.
L2VPN Nonstop
Routing
The L2VPN Nonstop Routing (NSR) feature avoids label distribution path
(LDP) sessions from flapping on events such as process failures (crash) and
route processor failover (RP FO). NSR on process failure (crash) is supported
by performing RP FO, if you have enabled NSR using NSR process failure
switchover.
NSR enables the router (where failure has occurred) to maintain the
control plane states without a graceful restart (GR). NSR, by definition, does
not require any protocol extension and typically uses Stateful Switch Over
(SSO) to maintain it’s control plane states.
L2TPv3 over
IPv6
A L2TPv3 over IPv6 tunnel is a static L2VPN cross-connect that uses Layer 2 Tunneling Protocol version 3 (L2TPv3) over IPv6,
with a unique IPv6 source address for each cross-connect. The L2TPv3 over IPv6 tunnels consists of one L2TPv3 tunnel for each
subscriber VLAN. The unique IPv6 address completely identifies the customer, and the service that is delivered.
Note
L2TPv3 over IPv6 tunnels are supported on the ASR 9000 Enhanced Ethernet line cards by a scale of 15000 crossconnects for
each router and line card.
Note
nV satellite access interfaces do not support L2TPv3 over IPv6.
Overview
L2TPv3 defines the
L2TP protocol for tunneling Layer 2 payloads over an IP core network using
Layer 2 virtual private networks (VPNs). Traffic between two customer network
sites is encapsulated in IP packets carrying L2TP data messages (payload) and
sent across an IP network. The backbone routers of the IP network treat this
payload in the same manner as it treats any other IP traffic. Implementing
L2TPv3 over IPv6 provides an opportunity to utilize unique source IPv6
addresses to directly identify Ethernet attachment circuits. In this case,
processing of the L2TPv3 session ID is bypassed; this is because each tunnel
has only one associated session. This local optimization, however, does not
hinder the ability to continue supporting circuit multiplexing through the
session ID for other L2TPv3 tunnels on the same router.
Traffic Injection
from L2TPv3 over IPv6 Tunnel feature allows you to inject diagnostic traffic
through Layer 2 Tunneling Protocol version 3 (L2TPv3) Switched Port Analyzer
(SPAN) tunnel. The diagnostic traffic allows you to monitor and troubleshoot
the network traffic. You can send the diagnostic traffic from customer office
(CO) using traffic generator towards the customer or towards the network.
In previous releases, with traffic mirroring feature the user was only
able to send the mirrored traffic from customer towards the monitoring device,
the mirror tunnel was unidirectional.
Traffic mirroring
copies traffic from one or more source ports and sends the copied traffic to
one or more destinations for analysis by a network analyzer or other monitoring
device. Traffic mirroring does not affect the flow of traffic on the source
interfaces or sub-interfaces, and allows the mirrored traffic to be sent to a
destination interface or sub-interface
Restrictions
This feature is
not supported on bundle and sub-bundle interfaces, supported only on main and
sub interfaces.
Diagnostic
traffic directed from network to customer does not traverse the same path as
the actual non-diagnostic network to customer traffic. As a result, any issue
with the core facing interface is not diagnosed.
Diagnostic
traffic will mix with the actual customer traffic. It is the responsibility of
CO to ensure that it does not cause any problems to the customer, and CO is
able to differentiate diagnostic traffic from customer traffic in the SPAN
tunnel.
Physical port
features are not available in the inward inject path, so the problems in the
physical port features, such as, EOAM or BIA MAC are not diagnosed.
Bundle and
other hash calculations, such as, ECMP, are not available, so the only customer
interface supported is a physical interface.
For Layer 3,
only IPv4 and IPv6 diagnostic payload is supported.
Topology
Figure 10. Traffic
Injection from L2TPv3 over IPv6 Tunnel
Consider a topology
where an L2TPv3 tunnel is created between two ASR 9000 devices. Customer Office
(CO) sends diagnostic traffic using traffic generator over L2TPv3 over IPv6
tunnel to the ASR 9000 router. The ASR 9000 router on the left-hand side sends
the diagnostic traffic towards the customer as though it is sent from the
network or sends the diagnostic traffic towards the network as though it is
sent from the customer.
The diagnostic
traffic header contains destination MAC address, source MAC address, and IP
payload. If the header contains destination MAC address of the ASR 9000 router,
the diagnostic traffic is sent to the network as though it sent from the
customer. If the header contains source MAC address of the ASR 9000 router, the
diagnostic traffic is sent to the customer as though it sent from the network.
Configure Traffic
Injection from L2TPv3 over IPv6 Tunnel
Perform these tasks on ASR 9000
router, which is on the left-hand side to configure Traffic Injection from
L2TPv3 over IPv6 Tunnel feature,
Create a pseudowire monitor session with inject interface
Attach the monitor session to an interface which needs to be
spanned
Configure L2VPN xconnect with monitor session
/* Create a pseudowire monitor session with inject interface */
Router# configure
Router(config)# monitor-session span1
Router(config-mon)# destination pseudowire
Router(config-mon)# inject-interface tenGigE 0/1/0/0/0
Router(config-mon)# commit
Router(config-mon)# end
/* Attach the monitor session to an interface which needs to be spanned */
Router# configure
Router(config)# int tenGigE 0/1/0/0/0
Router(config-subif)# monitor-session span1 ethernet
Router(config-if-mon)# commit
/* Configure L2VPN xconnect with monitor session */
Router(config)# l2vpn
Router(config-l2vpn)# xconnect group xc-span1
Router(config-l2vpn-xc)# p2p span-session1
Router(config-l2vpn-xc-p2p)# monitor-session span1
Router(config-l2vpn-xc-p2p)# neighbor ipv6 1112::1:1 pw-id 101
Router(config-l2vpn-xc-p2p-pw)# pw-class ts
Router(config-l2vpn-xc-p2p-pw)# source 1111::1:1
Router(config-l2vpn-xc-p2p-pw)# l2tp static local cookie size 8 value 0x1 0xa1 local session 101
Router(config-l2vpn-xc-p2p-pw)# l2tp static remote cookie size 8 value 0xa1 0x1 remote session 101
Router(config-l2vpn-xc-p2p-pw)# commit
Router(config-l2vpn-xc-p2p-pw)# end
Verify that the source MAC address and destination MAC address are
matching.
/* Verify that the source MAC address is matching */
Router#show monitor-session span1 counters
Monitor-session span1
TenGigE0/1/0/0/0.1
Rx replicated: 248 packets, 247086 octets
Tx replicated: 20001 packets, 20000094 octets
Non-replicated: 0 packets, 0 octets
Router#show interface tenGigE 0/1/0/7/8 accounting
TenGigE0/1/0/7/8.1
Protocol Pkts In Chars In Pkts Out Chars Out
IPV6_UNICAST 10001 10480072 10005 10480632
IPV6_MULTICAST 1 104 0 0
IPV6_ND 2 212 1 72
Router#show interface tenGigE 0/1/0/0/0 accounting
TenGigE0/1/0/0/0.1
Protocol Pkts In Chars In Pkts Out Chars Out
IPV6_UNICAST 2 136 10002 9780144
IPV6_ND
/* Verify that the destination MAC address is matching */
Router#show monitor-session counters
Monitor-session span1
TenGigE0/1/0/0/0.1
Rx replicated: 10001 packets, 10000094 octets
Tx replicated: 1 packets, 94 octets
Non-replicated: 0 packets, 0 octets
Router#show interface tenGigE 0/1/0/7/8 accounting
TenGigE0/1/0/7/8.1
Protocol Pkts In Chars In Pkts Out Chars Out
IPV6_UNICAST 10000 10480000 10000 10480000
IPV6_MULTICAST 0 0 1 104
IPV6_ND 0 0 1 104
Router#show interface tenGigE 0/1/0/0/0 accounting
TenGigE0/1/0/0/0.1
Protocol Pkts In Chars In Pkts Out Chars Out
IPV6_UNICAST 10000 9780000 0 0
IPV6_ND 1 82 1 72
L2TPv3 over IPv4
Layer 2 Tunneling Protocol version 3 (L2TPv3) over IPv4 provides a dynamic mechanism for
tunneling Layer 2 (L2) circuits across a packet-oriented data network, with multiple
attachment circuits multiplexed over a single pair of IP address endpoints, using the
L2TPv3 session ID as a circuit discriminator.
The following figure shows how the L2TPv3 feature is used to set up VPNs using Layer 2 tunneling over an IP network. All traffic
between two customer network sites is encapsulated in IP packets carrying L2TP data messages and sent across an IP network.
The backbone routers of the IP network treat the traffic as any other IP traffic and needn’t know anything about the customer
networks.
Figure 11. L2TPv3 Operation
In the above figure the PE routers R1 and R2 provide L2TPv3 services. The R1 and R2 routers communicate with each other using
a pseudowire over the IP backbone network through a path comprising the interfaces int1 and int2, the IP network, and interfaces int3 and int4. The CE routers R3 and R4 communicate through a pair of cross-connected Ethernet or 802.1q VLAN interfaces using an L2TPv3
session. The L2TPv3 session tu1 is a pseudowire configured between interface int1 on R1 and interface int4 on R2. Any packet
arriving on interface int1 on R1 is encapsulated and sent through the pseudowire control-channel (tu1) to R2. R2 decapsulates
the packet and sends it on interface int4 to R4. When R4 needs to send a packet to R3, the packet follows the same path in
reverse.
Note
L2TPv3 over IPv4 feature is supported only on Cisco ASR 9000 High Density 100GE Ethernet line cards.
Note
nV satellite access interfaces do not support L2TPv3 over IPv4.
A single-segment
pseudowire (SS-PW) is a point-to-point pseudowire (PW) where the PW segment is
present between two PE routers.
In this feature, a
single-segment pseudowire is established between two PE routers of the same
autonomous system (AS) dynamically using the FEC 129 information. The objective
of this feature is to ensure interoperability of the Cisco routers with the
third-party routers.
Active and Passive
Signaling
The T-PE on which the
SS-PW is initiated and the signaling message is transmitted from is called as
the source-terminating PE (ST-PE). The T-PE that waits and responds to the
SS-PW signaling message is called the target-terminating PE (TT-PE).
The signaling flow from the ST-PE to TT-PE is referred to as the forward
direction signaling or the active signaling. The signaling flow from the TT-PE
to ST-PE is referred to as the reverse direction signaling or the passive
signaling.
Generally, the PE with the highest prefix address takes the active role
and becomes the ST-PE, and the other PE becomes the passive TT-PE.
The following figure illustrates the SS-PW signaling flow between ST-PE
and TT-PE:
Figure 12. Single-Segment
Pseudowire Between ST-PE and TT-PE
Functionality of
Dynamic Single Segment Pseudowire
The dynamic discovery
of the pseudowire path from the ST-PE to the T-PE is achieved using the L2
route table. The route table entries, that is, a list of prefix and associated
next-hops to the L2VPN are populated by BGP.
Note
In Release 5.1.2,
Cisco supports only the routable prefix to reach the TAII on the T-PE. The
routable prefix is the neighbor address of the targeted-LDP session. The
reachability of packets from the source to the destination is achieved by user
configurations (see
Configuring L2VPN Single Segment Pseudowire)
However, BGP supports MS-PW Subsequent Address Family Identifiers (SAFI) that
is used to exchange the L2 routes across all the PEs. SS-PW uses the BGP MS-PW
address family to function. To ensure interoperability with other third-party
routers, Cisco advertises a single BGP MS-PW route per T-PE where the value of
AC-ID (attachment circuit-identifier) is a wild-card entry.
The supported
pseudowire features are pw-status, pw-grouping, and tag-impose vlan.
The following figure
illustrates the E-line Services Network with SS-PWs:
Figure 13. E-Line
Services Network with SS-PWs
Prerequisites for
Configuring L2VPN Single Segment Pseudowires
MPLS LDP, IGP, BGP,
L2VPN, and interfaces must be configured on the two end points of the PW:
Configuring MPLS Label Distribution Protocol.
Configuring Interior Gateway Protocol (IGP).
Configure Border Gateway Protocol (BGP).
Configuring an Interface or Connection for L2VPN.
Restrictions for
Configuring L2VPN Single Segment Pseudowires
The routed
pseudowire can only be enabled on Virtual Private Wire Service (VPWS) cross
connects.
A cross-connect
cannot have both ends configured as “neighbor routed” pseudowire.
SS-PW is not
supported as the other member of the cross-connect, that is, at a T-PE, one end
of the cross-connect can be the termination of the SS-PW and the other end can
either be an attachment circuit (AC) or a PW-HE.
Source AII and
AC-ID (attachment circuit identifier) are unique per router.
L2TP and MPLS
static are not supported.
Configuring L2VPN
Single Segment Pseudowire
To configure single
segment pseudowire in the network, do the following:
This procedure
is used to overwrite the default BGP Route Distinguisher (RD) auto-generated
value and also the Autonomous System Number (ASN) and Route Identifier (RID) of
BGP.
Specifies the
L2VPN address family of the neighbor and enters address family configuration
mode.
Step 6
Use the
commit or
end command.
commit - Saves the configuration changes and
remains within the configuration session.
end - Prompts user to take one of these actions:
Yes - Saves configuration
changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
EVPN Virtual Private Wire Service
(VPWS)
The EVPN-VPWS is a BGP control plane solution for point-to-point services. It implements the signaling and encapsulation techniques
for establishing an EVPN instance between a pair of PEs. It has the ability to forward traffic from one network to another
without MAC lookup. The use of EVPN for VPWS eliminates the need for signaling single-segment and multi-segment PWs for point-to-point
Ethernet services. You can also configure the PWHE interface and a bridge domain access pseudowire using EVPN-VPWS.
EVPN-VPWS single homed technology works on IP and MPLS core; IP core to support BGP and MPLS core for switching packets between
the endpoints.
Information About EVPN-VPWS Single
Homed
The EVPN-VPWS single homed solution requires per EVI Ethernet Auto Discovery route. EVPN defines a new BGP Network Layer Reachability
Information (NLRI) used to carry all EVPN routes. BGP Capabilities Advertisement used to ensure that two speakers support
EVPN NLRI (AFI 25, SAFI 70) as per RFC 4760.
The architecture for EVPN VPWS is that
the PEs run Multi-Protocol BGP in control-plane. The following image describes the
EVPN-VPWS configuration:
The VPWS service on PE1 requires the following three elements to be specified
at configuration time:
The VPN ID (EVI)
The local AC identifier (AC1) that identifies the local end of
the emulated service.
The remote AC identifier (AC2) that identifies the remote end of
the emulated service.
PE1 allocates a MPLS label per local AC for reachability.
The VPWS service on PE2 is set in the same manner as PE1. The three same
elements are required and the service configuration must be symmetric.
PE2 allocates a MPLS label per local AC for reachability.
PE1 advertise a single EVPN per EVI Ethernet AD route for each local endpoint
(AC) to remote PEs with the associated MPLS label.
PE2 performs the same task.
On reception of EVPN per EVI EAD route from PE2, PE1 adds the entry to its
local L2 RIB. PE1 knows the path list to reach AC2, for example, next hop is
PE2 IP address and MPLS label for AC2.
PE2 performs the same task.
Benefits of EVPN-VPWS
The following are the benefits of EVPN-VPWS:
Scalability is achieved
without signaling pseudowires.
Ease of provisioning
Pseudowires (PWs) are
not used.
Leverages BGP best
path selection (optimal forwarding).
Prerequisites for
EVPN-VPWS
Ensure BGP is
configured for EVPN SAFI.
BGP session
between PEs with 'address-family l2vpn evpn' to exchange EVPN routes.
Restrictions for
EVPN-VPWS
The VPN ID is unique per router.
When specifying a list of route targets, they must be unique per PE (per BGP address-family).
On versions earlier than IOS XR release 6.7.1, MTU is not signaled and the MTU mismatch is ignored with no interoperability
issues.
On versions starting from IOS XR release 6.7.1, L3 MTU is advertised by default and the MTU mismatch is enforced by default.
On versions earlier than IOS XR release 7.0.x, MTU is not signaled and the MTU mismatch is ignored with no interoperability
issues.
On versions later than IOS XR release 7.0.x, L3 MTU is advertised by default and the MTU mismatch is enforced by default.
But this results in interoperability issues with IOS XR release 7.3.2, if transmit-l2-mtu is configured since L3 and L2 MTUs
do not match. You can configure transmit-mtu-zero and ignore-mtu-mismatch commands to avoid this situation.
On versions later than IOS XR release 7.3.2, MTU of 0 is advertised by default, and the MTU mismatch is ignored by default.
L2 MTU can be advertised using the transmit-l2-mtu command, and MTU mismatch can be enforced with enforce-mtu-mismatch command.
How to Implement
Point to Point Layer 2 Services
This section
describes the tasks required to implement Point to Point Layer 2 Services:
Configuring an
Interface or Connection for Point to Point Layer 2 Services
Perform this task to
configure an interface or a connection for Point to Point Layer 2 Services.
RP/0/RSP0/CPU0:router# show qos interface gigabitethernet 0/0/0/0 input serpol1
(Optional)
Displays the QoS service policy you defined.
Configuring an L2VPN
Quality of Service Policy in VLAN Mode
This procedure
describes how to configure a L2VPN QoS policy in VLAN mode.
Note
In VLAN mode, the interface name must include a subinterface.
For example: GigabitEthernet0/1/0/1.1. The l2transport command must follow the
interface type on the same CLI line. For example: interface GigabitEthernet
0/0/0/0.1 l2transport”.
Saves
configuration changes to the running configuration file and remains in the
configuration session.
Provisioning a
Global Multisegment Pseudowire Description
S-PE nodes must have
a description in the Pseudowire Switching Point Type-Length-Value (TLV). The
TLV records all the switching points the pseudowire traverses, creating a
helpful history for troubleshooting.
Each multisegment
pseudowire can have its own description. For instructions, see the “Provisioning a Cross-Connect
Description". If it does not have one, this global description is used.
Populates the
Pseudowire Switching Point TLV. This TLV records all the switching points the
pseudowire traverses.
Each
multisegment pseudowire can have its own description. If it does not have one,
this global description is used.
Step 4
commit
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# commit
Saves
configuration changes to the running configuration file and remains in the
configuration session.
Provisioning a
Cross-Connect Description
S-PE nodes must have
a description in the Pseudowire Switching Point TLV. The TLV records all the
switching points the pseudowire traverses, creating a history that is helpful
for troubleshooting.
SUMMARY STEPS
configure
l2vpn
xconnect groupgroup-name
p2pxconnect-name
description
value
commit
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters the
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router(config)# l2vpn
Enters L2VPN
configuration mode.
Step 3
xconnect groupgroup-name
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# xconnect group MS-PW1
Configures a
cross-connect group name using a free-format 32-character string.
Saves
configuration changes to the running configuration file and remains in the
configuration session.
Provisioning
Switching Point TLV Security
For security
purposes, the TLV can be hidden, preventing someone from viewing all the
switching points the pseudowire traverses.
Virtual Circuit
Connection Verification (VCCV) may not work on multisegment pseudowires with
the
switching-tlv
parameter set to “hide”. For more information on VCCV, see the “Virtual Circuit Connection
Verification on L2VPN".
Saves
configuration changes to the running configuration file and remains in the
configuration session.
Enabling
Multisegment Pseudowires
Use the
pw-status command after you enable the
pw-status command. The
pw-status command is disabled by default. Changing the
pw-status command reprovisions all pseudowires
configured under L2VPN.
SUMMARY STEPS
configure
l2vpn
pw-status
commit
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters the
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router(config)# l2vpn
Enters Layer 2
VPN configuration mode.
Step 3
pw-status
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# pw-status
Enables all
pseudowires configured on this Layer 2 VPN.
Note
Use the
pw-status disable command to disable
pseudowire status.
Step 4
commit
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# commit
Saves
configuration changes to the running configuration file and remains in the
configuration session.
Configuring
Pseudowire Redundancy
Pseudowire redundancy allows you to configure a backup pseudowire in
case the primary pseudowire fails. When the primary pseudowire fails, the PE
router can switch to the backup pseudowire. You can elect to have the primary
pseudowire resume operation after it becomes functional.
These topics describe how to configure pseudowire redundancy:
Configuring Point-to-Point Pseudowire Redundancy
Perform this task to configure point-to-point pseudowire redundancy
for a backup delay.
This command specifies how long the primary pseudowire should
wait after it becomes active to take over from the backup pseudowire.
Use the
delay keyword to specify the number
of seconds that elapse after the primary pseudowire comes up before the
secondary pseudowire is deactivated. The range is from 0 to 180.
Use the
never keyword to specify that the
secondary pseudowire does not fall back to the primary pseudowire if the
primary pseudowire becomes available again, unless the secondary pseudowire
fails.
When you issue the
end command, the system prompts you to
commit changes:
Uncommitted changes found, commit them before exiting(yes/no/cancel)?
[cancel]:
Entering
yes saves configuration changes to the running
configuration file, exits the configuration session, and returns the router to
EXEC mode.
Entering
no exits the configuration session and returns the
router to
EXEC mode
without committing the configuration changes.
Entering
cancel leaves the router in the current
configuration session without exiting or committing the configuration changes.
Use the
commit command to save the configuration
changes to the running configuration file and remain within the configuration
session.
Forcing a Manual Switchover to the Backup Pseudowire
To force the router to switch over to the backup or switch back to
the primary pseudowire, use the
l2vpn switchover command in .EXEC mode
A manual switchover is made only if the peer specified in the
command is actually available and the cross-connect moves to the fully active
state when the command is entered.
Configuring a Backup
Pseudowire
Perform this task to
configure a backup pseudowire for a point-to-point neighbor.
This command
specifies how long the primary pseudowire should wait after it becomes active
to take over for the backup pseudowire.
Use the
delay keyword
to specify the number of seconds that elapse after the primary pseudowire comes
up before the secondary pseudowire is deactivated. The range, in seconds, is
from 0 to 180.
Use the
never keyword
to specify that the secondary pseudowire does not fall back to the primary
pseudowire if the primary pseudowire becomes available again, unless the
secondary pseudowire fails.
Configures
the backup pseudowire for the cross-connect.
Use the
neighbor
keyword to specify the peer to the cross-connect. The A.B.C.D argument is the
IPv4 address of the peer.
Use the
pw-id keyword
to configure the pseudowire ID. The range is from 1 to 4294967295.
Step 11
Use the
commit or
end command.
commit -
Saves the configuration changes and remains within the configuration session.
end - Prompts
user to take one of these actions:
Yes - Saves
configuration changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Forcing a Manual
Switchover to the Backup Pseudowire
To force the router to switch over to the backup or primary pseudowire,
use the
l2vpn switchover command in EXEC mode.
A manual switchover is made only if the peer specified in the command is
actually available and the cross-connect moves to the fully active state when
the command is entered.
Configuring
Preferred Tunnel Path
This procedure
describes how to configure a preferred tunnel path.
Note
The tunnel used for the
preferred path configuration is an MPLS Traffic Engineering (MPLS-TE) tunnel.
Configures
preferred path tunnel settings. If the fallback disable configuration is used
and once the TE/TP tunnel is configured
as the preferred path goes down, the corresponding pseudowire can also go down.
Step 6
Use the
commit or
end command.
commit - Saves the configuration changes and
remains within the configuration session.
end - Prompts user to take one of these actions:
Yes - Saves configuration
changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Configuring PW
Status OAM
Perform this task to configure
pseudowire status OAM.
Enables flow based load balancing for all the pseudowires and
bundle EFPs under L2VPN, unless otherwise explicitly specified for pseudowires
via pseudowire class and bundles via EFP-hash.
Step 4
endorcommit
Example:
RP/0/RSP0RP0/CPU0:router(config-l2vpn)# end
or
RP/0/RSP0RP0/CPU0:router(config-l2vpn)# commit
Saves configuration changes.
When you issue the
end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before exiting(yes/no/cancel)?[cancel]:
Entering
yes saves configuration changes to the running
configuration file, exits the configuration session, and returns the router to
EXEC mode.
Entering no
exits the configuration session and returns the router to
EXEC mode without committing the configuration
changes.
Entering
cancel leaves the router in the current configuration
session without exiting or committing the configuration changes.
Use the
commit command to save the configuration changes to the
running configuration file and remain within the configuration session.
Enabling Flow-based
Load Balancing for a Pseudowire Class
Perform this task to enable
flow-based load balancing for a pseudowire class.
commit - Saves the configuration changes
and remains within the configuration session.
end - Prompts user to take one of these
actions:
Yes - Saves
configuration changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel -
Remains in the configuration mode, without committing the configuration
changes.
Setting Up Your
Multicast Connections
Refer to the
Implementing Multicast Routing on Cisco ASR 9000 Series Aggregation
Services Routers module of the
Cisco ASR 9000 Series Aggregation Services Router Multicast
Configuration Guide and the
Multicast Routing and Forwarding Commands on Cisco ASR 9000 Series
Aggregation Services Routers module of the
Cisco ASR 9000 Series Aggregation Services Router Multicast Command
Reference.
SUMMARY STEPS
configure
multicast-routing [address-family ipv4]
interface all
enable
exit
router igmp
version {1 | 2 |
3}
endorcommit
show pim [ipv4]
group-map
[ip-address-name] [info-source]
show pim [vrf
vrf-name] [ipv4] topology
[source-ip-address [group-ip-address] |
entry-flag
flag | interface-flag | summary] [route-count]
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters global
configuration mode.
Step 2
multicast-routing [address-family ipv4]
Example:
RP/0/RSP0/CPU0:router(config)# multicast-routing
Enters multicast
routing configuration mode.
These multicast
processes are started:
MRIB, MFWD, PIM, and IGMP.
For
IPv4,
IGMP version 3 is enabled by default.
For IPv4, use the
address-family ipv4
keywords
Step 3
interface all
enable
Example:
RP/0/RSP0/CPU0:router(config-mcast-ipv4)# interface all enable
Enables
multicast routing and forwarding on all new and existing interfaces.
Step 4
exit
Example:
RP/0/RSP0/CPU0:router(config-mcast-ipv4)# exit
Exits multicast
routing configuration mode, and returns the router to the parent configuration
mode.
Note
For Leaf PEs,
if you intend to enable IGMPSN on the bridge domain, ensure that you configure
internal querier inside the IGMPSN profile.
Step 5
router igmp
Example:
RP/0/RSP0/CPU0:router(config)# router igmp
(Optional)
Enters router IGMP configuration mode.
Step 6
version {1 | 2 |
3}
Example:
RP/0/RSP0/CPU0:router(config-igmp)# version 3
(Optional)
Selects the IGMP version that the router interface uses.
The default for IGMP
is version 3.
Host receivers must
support IGMPv3 for PIM-SSM operation.
If this command is
configured in router IGMP configuration mode, parameters are inherited by all
new and existing interfaces. You can override these parameters on individual
interfaces from interface configuration mode.
Step 7
endorcommit
Example:
RP/0/RSP0/CPU0:router(config-l2vpn-bg-bd)# end
or
RP/0/RSP0/CPU0:router(config-l2vpn-bg-bd)#commit
Saves configuration changes.
When you issue the
end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before exiting(yes/no/cancel)?[cancel]:
Entering
yes saves configuration changes to the running
configuration file, exits the configuration session, and returns the router to
EXEC mode.
Entering
no exits the configuration session and returns the
router to
EXEC mode without committing the configuration
changes.
Entering
cancel leaves the router in the current configuration
session without exiting or committing the configuration changes.
Use the
commit command to save the configuration changes to the
running configuration file and remain within the configuration session.
Step 8
show pim [ipv4]
group-map
[ip-address-name] [info-source]
Example:
RP/0//CPU0:router# show pim ipv4 group-map
(Optional)
Displays group-to-PIM mode mapping.
Step 9
show pim [vrf
vrf-name] [ipv4] topology
[source-ip-address [group-ip-address] |
entry-flag
flag | interface-flag | summary] [route-count]
Example:
RP/0/RSP0/CPU0:router# show pim topology
(Optional)
Displays PIM topology table information for a specific group or all groups.
Configuring AToM IP
Interworking
Perform this task to configure AToM IP
Interworking.
SUMMARY STEPS
configure
l2vpn
xconnect groupgroup-name
p2pxconnect-name
interworking
ipv4
Use the
commit or
end command.
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters the
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router(config)# l2vpn
Enters L2VPN
configuration mode.
Step 3
xconnect groupgroup-name
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# xconnect group grp_1
Enters the name
of the cross-connect group.
Step 4
p2pxconnect-name
Example:
RP/0/RSP0/CPU0:router(config-l2vpn-xc)# p2p vlan1
Enters a name
for the point-to-point cross-connect.
Configures the
backup pseudowire for the cross-connect.
Step 7
Use the
commit or
end command.
commit -
Saves the configuration changes and remains within the configuration session.
end - Prompts
user to take one of these actions:
Yes - Saves
configuration changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Configuring L2VPN
Nonstop Routing
Perform this task to
configure L2VPN Nonstop Routing.
SUMMARY STEPS
configure
l2vpn
nsr
logging
nsr
Use the
commit or
end command.
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router(config)# l2vpn
Enters the
Global Configuration mode.
Step 3
nsr
Example:
RP/0/RSP0/CPU0:router (config-l2vpn)# nsr
Enables L2VPN
nonstop routing.
Step 4
logging
nsr
Example:
RP/0/RSP0/CPU0:router (config-l2vpn)# logging nsr
Enables logging
of NSR events.
Step 5
Use the
commit or
end command.
commit - Saves the configuration changes and
remains within the configuration session.
end - Prompts user to take one of these actions:
Yes - Saves configuration
changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Configure MPLS LDP Nonstop Routing
Perform this task to enable Label Distribution Protocol (LDP) Nonstop Routing (NSR) for synchronizing label information between
active and standby LDPs. From Release 6.1.1 onwards, with the introduction of stateful LDP feature, you must explicitly configure
LDP NSR to synchronize label information between active and standby LDPs.
SUMMARY STEPS
configure
mpls ldp
nsr
Use the commit or end command.
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters Global Configuration mode.
Step 2
mpls ldp
Example:
RP/0/RSP0/CPU0:router(config)# mpls ldp
Enters MPLS LDP configuration mode.
Step 3
nsr
Example:
RP/0/RSP0/CPU0:router(config-ldp)# nsr
Enables LDP nonstop routing.
Step 4
Use the commit or end command.
commit - Saves the configuration changes and remains within the configuration session.
end - Prompts user to take one of these actions:
Yes - Saves configuration changes and exits the configuration session.
No - Exits the configuration session without committing the configuration changes.
Cancel - Remains in the configuration mode, without committing the configuration changes.
Configuring L2TPv3 over IPv6
Tunnels
Perform these tasks to configure the
L2TPv3 over IPv6 tunnels:
Configuring Neighbor
AFI for Pseudowire
Perform this task to
configure the neighbor AFI for pseudowire.
Restriction
L2TPv3 over IPv6Tunnels is supported only on layer 2 transport
sub-interfaces and not physical interfaces.
SUMMARY STEPS
configure
l2vpn
xconnect group group-name
p2p xconnect-name
interface type
interface-path-id
neighbor ipv6 X:X::X
pw-idpseudowire-id
Use the
commit or
end command.
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters the
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router (config)# l2vpn
Enters Layer 2
VPN configuration mode.
Step 3
xconnect group group-name
Example:
RP/0/RSP0/CPU0:router(config-l2vpn)# xconnect group grp_1
Configures a
cross-connect group and specifies it’s name.
Enters
pseudowire class submode, allows a pseudowire class template definition.
These keywords
can be configured in the pseudowire class (pw-class) configuration mode;
however, the keywords are not applicable for the
over
L2TPv3 over IPv6
tunnels:
(Optional)
Configures a static remote session for the L2TP pseudowire.
Note
When
configured, remote session value(expected at the decapsulation side) is used
for encapsulation- side processing, and the value in the session value field of
the L2TPv3 header is programmed.
Step 9
Use the
commit or
end command.
commit -
Saves the configuration changes and remains within the configuration session.
end - Prompts
user to take one of these actions:
Yes - Saves
configuration changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Configuring Local
And Remote Cookies
Perform this task to
configure local and remote cookies.
SUMMARY STEPS
configure
l2vpn
xconnect groupgroup-name
p2pxconnect-name
interface typeinterface-path-id
neighbor ipv6peer-addresspw-idpseudowire-id
l2tp static local cookie
sizebytes
l2tp static local cookie
sizebytes
Use the
commit or
end command.
DETAILED STEPS
Step 1
configure
Example:
RP/0/RSP0/CPU0:router# configure
Enters the
Global Configuration mode.
Step 2
l2vpn
Example:
RP/0/RSP0/CPU0:router (config)# l2vpn
Enters Layer 2
VPN configuration mode.
Step 3
xconnect groupgroup-name
Example:
RP/0/RSP0/CPU0:router (config-l2vpn)# xconnect group g1
L2TPv3 over Ipv4 Tunnels is supported only on layer 2 transport
sub-interfaces and not on physical interfaces. When an untagged traffic has to
be sent through L2TPv3 over IPv4, create a sub-interface with encapsulation as
untagged.
This example shows how to create a sub-interface with encapsulation as
untagged:
commit - Saves the configuration changes and
remains within the configuration session.
end - Prompts user to take one of these actions:
Yes - Saves
configuration changes and exits the configuration session.
No - Exits the
configuration session without committing the configuration changes.
Cancel - Remains in the
configuration mode, without committing the configuration changes.
Configuring L2TP Control-Channel
Parameters
L2TP control-channel parameters are used in control-channel authentication, keepalive
messages, and control-channel negotiation. In a L2tpv3 session, the same L2TP class
must be configured on both PE routers.
The following L2TP control-channel parameters can be configured in L2TP class
configuration mode:
Authentication for the L2TP control-channel
Password used for L2TP control-channel authentication
Retransmission parameters used for control messages.
Timeout parameters used for the control-channel.
Maintenance Parameters
L2TPv3 Control Message Hashing
Perform this task to create a template of L2TP control-channel parameters that can be
inherited by different pseudowire classes.
SUMMARY STEPS
configure
l2tp-classl2tp-class-name
authentication
password {0 | 7}
password
retransmit { initial retriesinitial-retries | retriesretries | timeout { max | min }
timeout }
Configures parameters that affect the retransmission of control packets.
initial retries—Specifies how many SCCRQs
are re-sent before giving up on the session. Range is 1 to 1000. The
default is 2.
retries—Specifies how many retransmission
cycles occur before determining that the peer PE router does not
respond. Range is 1 to 1000. The default is 15.
timeout { max | min
} —Specifies maximum and minimum retransmission intervals (in
seconds) for resending control packets. Range is 1 to 8. The default
maximum interval is 8; the default minimum interval is 1.
If the digest command is issued without the
secret keyword option, L2TPv3 integrity
checking is enabled.
{0 |
7}—Specifies the input format of the
shared secret. The default value is 0.
0—Specifies that a plain-text
secret is entered.
7—Specifies that an encrypted
secret is entered.
password—Defines the shared secret
between peer routers. The value entered for the
passwordargument must be in the format that matches the input format
specified by the {0 |
7} keyword option.
hash
{ MD5 |
SHA1}—Specifies the hash function to be used
in per-message digest calculations.
MD5—Specifies HMAC-MD5 hashing
(default value).
SHA1—Specifies HMAC-SHA-1
hashing.
Step 8
hidden
Example:
RP/0/RSP0/CPU0:router(config-l2tp-class)# hidden
Enables AVP hiding when sending control messages to an L2TPv3 peer.
Configuring L2VPN
Single Segment Pseudowire
To configure single
segment pseudowire in the network, do the following:
This procedure
is used to overwrite the default BGP Route Distinguisher (RD) auto-generated
value and also the Autonomous System Number (ASN) and Route Identifier (RID) of
BGP.
Establishes a bridge domain and enters L2VPN bridge group bridge domain configuration mode.
Step 6
neighbor evpn evivpn-idtargetac-id
Example:
RP/0/RSP0/CPU0:router(config-l2vpn-bg-bd)# neighbor evpn evi 100 target 12
Enables EVPN-VPWS endpoint on the p2p cross-connect.
Example
Configuration
Examples for Point to Point Layer 2 Services
This section includes these configuration examples:
L2VPN Interface
Configuration: Example
The following
example shows how to configure an L2VPN interface :
configure
interface GigabitEthernet0/0/0/0.1 l2transport
encapsulation dot1q 1
rewrite ingress tag pop 1 symmetric
end
Local Switching
Configuration: Example
This example shows how to configure
Layer 2 local switching:
configure
l2vpn
xconnect group examples
p2p example1
interface TenGigE0/7/0/6.5
interface GigabitEthernet0/4/0/30
commit
end
show l2vpn xconnect group examples
Legend: ST = State, UP = Up, DN = Down, AD = Admin Down, UR = Unresolved,
SB = Standby, SR = Standby Ready
XConnect Segment 1 Segment 2
Group Name ST Description ST Description ST
examples example1 UP Te0/7/0/6.5 UP Gi0/4/0/30 UP
Local Connection
Redundancy Configuration: Example
The following example shows how to
configure the LCR on PoA1:
! LCR - CE1
group 107
mlacp node 1
mlacp system mac 0001.0001.0107
mlacp system priority 107
member
neighbor 200.0.2.1
!
! LCR - CE2
group 207
mlacp node 1
mlacp system mac 0001.0001.0207
mlacp system priority 207
member
neighbor 200.0.2.1
!
interface Bundle-Ether107
description CE5 - LCR
mlacp iccp-group 107
mlacp port-priority 10
no shut
interface Bundle-Ether207
description CE6 - LCR
mlacp iccp-group 207
mlacp port-priority 10
no shut
interface bundle-e107.1 l2t
description CE5 - LCR
encap dot1q 107 second 1
rewrite ingress tag pop 2 symmetric
interface bundle-e207.1 l2t
description CE2 - LCR
encap dot1q 207 second 1
rewrite ingress tag pop 2 symmetric
interface bundle-e307.1 l2t
description PE2 - LCR
encap dot1q 1
rewrite ingress tag pop 1 symmetric
l2vpn
xconnect group lcr-scale
p2p lcr-1
interface bundle-e107.1
interface bundle-e207.1
backup interface bundle-e307.1
This sample configuration shows how
to configure PW status OAM functionality:
l2vpn
pw-oam refresh transmit 100
commit
Viewing Pseudowire
Status: Example
show l2vpn
xconnect
RP/0/RSP0/CPU0:router# show l2vpn xconnect
Legend: ST = State, UP = Up, DN = Down, AD = Admin Down, UR = Unresolved,
LU = Local Up, RU = Remote Up, CO = Connected
XConnect Segment 1 Segment 2
Group Name ST Description ST Description ST
------------------------ ------------------------- -------------------------
MS-PW1 ms-pw1 UP 70.70.70.70 100 UP 90.90.90.90 300 UP
--------------------------------------------------------------------------------
show l2vpn xconnect
detail
RP/0/RSP0/CPU0:router# show l2vpn xconnect detail
Group MS-PW1, XC ms-pw1, state is up; Interworking none
PW: neighbor 70.70.70.70, PW ID 100, state is up ( established )
PW class not set
Encapsulation MPLS, protocol LDP
PW type Ethernet VLAN, control word enabled, interworking none
PW backup disable delay 0 sec
Sequencing not set
PW Status TLV in use
MPLS Local Remote
------------ ------------------------------ -----------------------------
Label 16004 16006
Group ID 0x2000400 0x2000700
Interface GigabitEthernet0/1/0/2.2 GigabitEthernet0/1/0/0.3
MTU 1500 1500
Control word enabled enabled
PW type Ethernet VLAN Ethernet VLAN
VCCV CV type 0x2 0x2
(LSP ping verification) (LSP ping verification)
VCCV CC type 0x5 0x7
(control word) (control word)
(router alert label)
(TTL expiry) (TTL expiry)
------------ ------------------------------ -----------------------------
Incoming Status (PW Status TLV):
Status code: 0x0 (Up) in Notification message
Outgoing PW Switching TLVs (Label Mapping message):
Local IP Address: 80.80.80.80, Remote IP address: 90.90.90.90, PW ID: 300
Description: S-PE1 MS-PW between 70.70.70.70 and 90.90.90.90
Outgoing Status (PW Status TLV):
Status code: 0x0 (Up) in Notification message
Statistics:
packet totals: receive 0
byte totals: receive 0
Create time: 04/04/2008 23:18:24 (00:01:24 ago)
Last time status changed: 04/04/2008 23:19:30 (00:00:18 ago)
PW: neighbor 90.90.90.90, PW ID 300, state is up ( established )
PW class not set
Encapsulation MPLS, protocol LDP
PW type Ethernet VLAN, control word enabled, interworking none
PW backup disable delay 0 sec
Sequencing not set
PW Status TLV in use
MPLS Local Remote
------------ ------------------------------ -----------------------------
Label 16004 16006
Group ID 0x2000800 0x2000200
Interface GigabitEthernet0/1/0/0.3 GigabitEthernet0/1/0/2.2
MTU 1500 1500
Control word enabled enabled
PW type Ethernet VLAN Ethernet VLAN
VCCV CV type 0x2 0x2
(LSP ping verification) (LSP ping verification)
VCCV CC type 0x5 0x7
(control word) (control word)
(router alert label)
(TTL expiry) (TTL expiry)
------------ ------------------------------ -----------------------------
Incoming Status (PW Status TLV):
Status code: 0x0 (Up) in Notification message
Outgoing PW Switching TLVs (Label Mapping message):
Local IP Address: 80.80.80.80, Remote IP address: 70.70.70.70, PW ID: 100
Description: S-PE1 MS-PW between 70.70.70.70 and 90.90.90.90
Outgoing Status (PW Status TLV):
Status code: 0x0 (Up) in Notification message
Statistics:
packet totals: receive 0
byte totals: receive 0
Create time: 04/04/2008 23:18:24 (00:01:24 ago)
Last time status changed: 04/04/2008 23:19:30 (00:00:18 ago)
Configuring Any
Transport over MPLS: Example
This example shows you how to
configure Any Transport over MPLS (AToM):
config
l2vpn
xconnect group test
p2p test
interface POS 0/1/0/0.1
neighbor 10.1.1.1 pw-id 100
Configuring AToM IP
Interworking: Example
This example shows you how to
configure IP interworking:
config
l2vpn
xconnect group test
p2p test
interworking ipv4
Configuring PPP IP
Interworking: Example
This example shows you how to
configure PPP IP interworking:
For L2TPv3 over IPv6 tunnels, the
local and remote cookies are configured under the pseudowire. Support has been
extended for cookie roll-over that provides the ability to configure a
secondary local cookie. This example shows how to configure a cookie with size
0:
This example shows how to configure a cookie with size 4:
l2vpn
xconnect group g1
p2p xc3
interface GigabitEthernet0/0/0/4.2
neighbor ipv6 1111:2222::cdef pw-id 1
l2tp static local cookie size 4 value <0x0-0xffffffff>
l2tp static remote cookie size 4 value <0x0-0xffffffff>
This example shows how to configure a cookie with size 8 (the lower 4
bytes are entered first; followed by the higher 4 bytes):
l2vpn
xconnect group g1
p2p xc3
interface GigabitEthernet0/0/0/4.2
neighbor ipv6 1111:2222::cdef pw-id 1
l2tp static local cookie size 8 value <0x0-0xffffffff> <0x0-0xffffffff>
l2tp static remote cookie size 8 value <0x0-0xffffffff> <0x0-0xffffffff>
To support cookie roll-over on L2TPv3 over IPv6 tunnels, configure a
secondary local cookie. The local cookie secondary command specifies the
secondary cookie value on the local router.
Note
The primary and secondary cookies must be of the same size.
Primary or secondary local cookies must match the cookie value being received
from the remote end, otherwise, packets are dropped.
l2vpn
xconnect group g1
p2p xc3
interface GigabitEthernet0/0/0/4.2
neighbor ipv6 1111:2222::cdef pw-id 1
l2tp static local cookie secondary size 8 value <0x0-0xffffffff> <0x0-0xffffffff>
Enabling L2TP Static
Submode: Example
This example shows you how to
enable the L2TP static submode:
l2vpn
xconnect group g1
p2p xc3
interface GigabitEthernet0/0/0/4.2
neighbor ipv6 1111:2222::cdef pw-id 1
l2tp static
local cookie <>
Enabling TOS
Reflection in the L2TPv3 Header: Example
For L2TPv3 over IPv6 tunnels,
configurations are supported for each pseudowire class to enable type of
service (TOS) reflection, or to set a specific TOS value in the L2TPv3 header.
Note
By default, the TOS is copied over from the class of service
(COS) fields of the VLAN header. If the underlying packet is not an IPv4 or
IPv6 packet, the COS fields are copied from the VLAN header, even if a TOS
reflection is configured.
This example shows how to configure a TOS reflection in the L2TPv3
header:
l2vpn
pw-class ts
encapsulation l2tpv3
protocol l2tpv3
tos reflect
This example shows how to set a TOS value in the L2TPv3 header:
l2vpn
pw-class ts
encapsulation l2tpv3
protocol l2tpv3
tos value 64
Configuring TTL for
L2TPv3 over IPv6 Tunnels: Example
For L2TPv3 over IPv6 tunnels, TTL
configuration is supported in the pseudowire class.