Contents
- Layer 2 Local Switching
- Finding Feature Information
- Prerequisites for Layer 2 Local Switching
- Restrictions for Layer 2 Local Switching
- Cisco 7200 and 7500 Series Router Restrictions
- Cisco 7600 and 6500 Series Router Restrictions
- Cisco 10000 Series Router Restrictions
- Gigabit Switch Router Restrictions
- Unsupported Hardware
- Information About Layer 2 Local Switching
- Layer 2 Local Switching Overview
- NSF SSO—Local Switching Overview
- Layer 2 Local Switching Applications
- Access Circuit Redundancy Local Switching
- ACR for ATM-to-ATM Local Switching
- ACR for CEM-to-CEM Local Switching
- How to Configure Layer 2 Local Switching
- Configuring ATM-to-ATM PVC Local Switching and Same-Port Switching
- Configuring ATM-to-ATM PVP Local Switching
- Configuring ATM PVP Same-Port Switching
- Configuring ATM-to-Ethernet Port Mode Local Switching
- Configuring ATM-to-Ethernet VLAN Mode Local Switching
- Configuring Ethernet VLAN Same-Port Switching
- Configuring Ethernet Port Mode to Ethernet VLAN Local Switching
- Configuring ATM-to-Frame Relay Local Switching
- Configuring Frame Relay-to-Frame Relay Local Switching
- Configuring Frame Relay Same-Port Switching
- Configuring HDLC Local Switching
- Configuring ACR for ATM-to-ATM Local Switching
- Configuring CEM-to-CEM ACR Local Switching
- Verifying Layer 2 Local Switching
- Verifying Layer 2 Local Switching Configuration
- Verifying the NSF SSO Local Switching Configuration
- Troubleshooting Tips
- Configuration Examples for Layer 2 Local Switching
- Example: ATM-to-ATM Local Switching
- Example: ATM PVC Same-Port Switching
- Example: Configuring ATM PVP Same-Port Switching
- Example: ATM-to-Ethernet Local Switching
- Example: ATM-to-Ethernet VLAN Mode Local Switching
- Example: ATM-to-Ethernet Port Mode Local Switching
- Example: Ethernet VLAN Same-Port Switching
- Example: ATM-to-Frame Relay Local Switching
- Example: Frame Relay-to-Frame Relay Local Switching
- Example: Frame Relay DLCI Same-Port Switching
- Example: HDLC Local Switching
- Example: NSF SSO Ethernet Port Mode to Ethernet VLAN Local Switching
- Additional References for Layer 2 Local Switching
- Feature Information for Layer 2 Local Switching
Layer 2 Local Switching
The Layer 2 Local Switching feature allows you to switch Layer 2 data in two ways:
- Between two interfaces on the same router
- Between two circuits on the same interface port, which is called same-port switching
The interface-to-interface switching combinations supported by this feature are:
- ATM to ATM
- ATM to Ethernet
- ATM to Frame Relay
- Ethernet to Ethernet VLAN
- Frame Relay to Frame Relay (and Multilink Frame Relay in Cisco IOS Release 12.0(28)S and later)
- High-Level Data Link Control (HDLC)
The following same-port switching features are supported:
- Finding Feature Information
- Prerequisites for Layer 2 Local Switching
- Restrictions for Layer 2 Local Switching
- Information About Layer 2 Local Switching
- How to Configure Layer 2 Local Switching
- Configuration Examples for Layer 2 Local Switching
- Additional References for Layer 2 Local Switching
- Feature Information for Layer 2 Local Switching
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Layer 2 Local Switching
- You must enable Cisco Express Forwarding for the Cisco 7200 series router. You must use Cisco Express Forwarding or Distributed Cisco Express Forwarding for the Cisco 7500 series router. (Distributed Cisco Express Forwarding is enabled already by default on the Gigabit Switch Router [GSR]).
- For Frame Relay local switching, you must globally issue the frame-relay switching command.
Restrictions for Layer 2 Local Switching
- Cisco 7200 and 7500 Series Router Restrictions
- Cisco 7600 and 6500 Series Router Restrictions
- Cisco 10000 Series Router Restrictions
- Gigabit Switch Router Restrictions
- Unsupported Hardware
Cisco 7200 and 7500 Series Router Restrictions
- In ATM single cell relay AAL0, the ATM virtual path identifier/virtual channel identifier (VPI/VCI) values must match between the ingress and egress ATM interfaces on the Cisco 7200 series and 7500 series routers. If Layer 2 local switching is desired between two ATM VPIs and VCIs whose values do not match and are on two different interfaces, choose ATM AAL5. However, if the ATM AAL5 is using Operation, Administration, and Maintenance (OAM) transparent mode, the VPI and VCI values must match.
- NSF/SSO: Layer 2 local switching is supported on Cisco 7500 series routers.
Layer 2 local switching is supported on the following interface processors in the Cisco 7200 series routers:
- C7200-I/O-2FE
- C7200-I/O-GE+E (Only the Gigabit Ethernet port of this port adapter is supported.)
- C7200-I/O-FE
Layer 2 local switching is supported on the following interface processors in the Cisco 7500 series routers:
- GEIP (Gigabit Ethernet interface processor)
- GEIP+ (enhanced Gigabit Ethernet interface processor)
Layer 2 local switching is supported on the following port adapters in the Cisco 7200 and 7500 series routers:
- PA-FE-TX (single-port Fast Ethernet 100BASE-TX)
- PA-FE-FX (single-port Fast Ethernet 100BASE-FX)
- PA-2FE-TX (dual-port Fast Ethernet 100BASE-TX)
- PA-2FE-FX (dual-port Fast Ethernet 100BASE-FX)
- PA-4E (4-port Ethernet adapter)
- PA-8E (8-port Ethernet adapter)
- PA-4T (4-port synchronous serial port adapter)
- PA-4T+ (enhanced 4-port synchronous serial port adapter)
- PA-8T (8-port synchronous serial port adapter)
- PA-12E/2FE (12-port Ethernet/2-port Fast Ethernet (FE) adapter) [Cisco 7200 only]
- PA-GE (Gigabit Ethernet port adapter) [Cisco 7200 only]
- PA-H (single-port High-Speed Serial Interface (HSSI) adapter)
- PA-2H (dual-port HSSI adapter)
- PA-MC-8E1 (8-port multichannel E1 G.703/G.704 120-ohm interfaces)
- PA-MC-2EI (2-port multichannel E1 G.703/G.704 120-ohm interfaces)
- PA-MC-8T1 (8-port multichannel T1 with integrated data service units (DSUs) and channel service units CSUs))
- PA-MC-4T1 (4-port multichannel T1 with integrated CSUs and DSUs)
- PA-MC-2T1 (2-port multichannel T1 with integrated CSUs and DSUs)
- PA-MC-8TE1+ (8-port multichannel T1/E1)
- PA-MC-T3 (1-port multichannel T3 interface)
- PA-MC-E3 (1-port multichannel E3 interface)
- PA-MC-2T3+ (2-port enhanced multichannel T3 port adapter)
- PA-MC-STM1 (1-port multichannel STM-1 port adapter) [Cisco 7500 only]
- PA-T3 (single-port T3 port adapter)
- PA-E3 (single-port E3 port adapter)
- PA-2E3 (2-port E3 port adapter)
- PA-2T3 (2-port T3 port adapter)
- PA-POS-OC-3SML (single-port Packet over SONET (POS), single-mode, long reach)
- PA-POS-OC-3SMI (single-port PoS, single-mode, intermediate reach)
- PA-POS-OC-3MM (single-port PoS, multimode)
- PA-A3-OC-3 (1-port ATM OC-3/STM1 port adapter, enhanced)
- PA-A3-OC-12 (1-port ATM OC-12/STM-4 port adapter, enhanced) [Cisco 7500 only]
- PA-A3-T3 (DS3 high-speed interface)
- PA-A3-E3 (E3 medium-speed interface)
- PA-A3-8T1IMA (ATM inverse multiplexer over ATM port adapter with 8 T1 ports)
- PA-A3-8E1IMA (ATM inverse multiplexer over ATM port adapter with 8 E1 ports)
- PA-A6 (Cisco ATM Port Adapter)
Cisco 7600 and 6500 Series Router Restrictions
Layer 2 local switching supports the following port adapters and interface processors on the Cisco 7600-SUP720/MSFC3 router: - All port adapters on the Enhanced FlexWAN module
- All shared prot adaptors (SPAs) on the SIP-200 line cards
- On the Cisco 6500 series and 7600 series routers, only like-to-like local switching is supported (ATM to ATM and Frame Relay to Frame Relay).
- Same-port switching is not supported on the Cisco 6500 series and 7600 series routers.
Cisco 10000 Series Router Restrictions
For information about Layer 2 local switching on the Cisco 10000 series routers, see the Configuring Layer 2 Local Switching document.
Gigabit Switch Router Restrictions
- VPI/VCI rewrite is supported.
- All GSR line cards support Frame Relay-to-Frame Relay local switching.
- 8-port OC-3 ATM Engine 2 line cards support only like-to-like Layer 2 local switching.
- IP Service Engine (ISE) (Engine 3) line cards support like-to-like and any-to-any local switching. Non-ISE line cards support only like-to-like local switching.
Starting in Cisco IOS Release 12.0(31)S2, ISE customer edge-facing interfaces support the following types of like-to-like and any-to-any local switching:
 Note | Native Layer 2 Tunnel Protocol Version 3 (L2TPv3) tunnel sessions on customer edge-facing line cards can coexist with tunnel sessions that use a tunnel-server card. |
Starting in Cisco IOS Release 12.0(32)SY, customer edge-facing interfaces on Engine 5 SPAs and SPA Interface Processors (SIPs) support the following types of like-to-like local switching: For ATM-to-ATM local switching, the following ATM types are supported for the Layer 2 Local Switching feature: - Starting with Cisco IOS Release 12.0(30)S, you can use local switching and cell packing with ATM VP or VC mode on the GSR on IP Services Engine (ISE/Engine 3) line cards. For information about how to configure cell packing, refer to Any Transport over MPLS.
Unsupported Hardware
The following hardware is not supported:
- Cisco 7200—non-VXR chassis
- Cisco 7500—Route Switch Processor (RSP)1 and 2
- Cisco 7500—Versatile Interface Processor (VIP) 2-40 and below
- GSR—4-port OC-3 ATM Engine-0 line card
- GSR—4-port OC-12 ATM Engine-2 line card
- GSR—1-port OC-12 ATM Engine-0 line card
- GSR—Ethernet Engine-1, Engine-2, and Engine-4 line cards
Information About Layer 2 Local Switching
- Layer 2 Local Switching Overview
- NSF SSO—Local Switching Overview
- Layer 2 Local Switching Applications
- Access Circuit Redundancy Local Switching
Layer 2 Local Switching Overview
Local switching allows you to switch Layer 2 data between two interfaces of the same type (for example, ATM to ATM, or Frame Relay to Frame Relay) or between interfaces of different types (for example, Frame Relay to ATM) on the same router. The interfaces can be on the same line card or on two different cards. During these kinds of switching, the Layer 2 address is used, not any Layer 3 address.
Additionally, same-port local switching allows you to switch Layer 2 data between two circuits on the same interface.
NSF SSO—Local Switching Overview
Nonstop forwarding (NSF) and stateful switchover (SSO) improve the availability of the network by providing redundant Route Processors (RPs) and checkpointing of data to ensure minimal packet loss when the primary RP goes down. NSF/SSO support is available for the following locally switched attachment circuits:
Layer 2 Local Switching Applications
Incumbent local exchange carriers (ILECs) who use an interexchange carrier (IXC) to carry traffic between two local exchange carriers can use the Layer 2 Local Switching feature. Telecom regulations require the ILECs to pay the IXCs to carry that traffic. At times, the ILECs cannot terminate customer connections that are in different local access and transport areas (LATAs). In other cases, customer connections terminate in the same LATA, which may also be on the same router.
For example, company A has more than 50 LATAs across the country and uses three routers for each LATA. Company A uses companies B and C to carry traffic between local exchange carriers. Local switching of Layer 2 frames on the same router might be required.
Similarly, if a router is using, for example, a channelized interface, it might need to switch incoming and outgoing traffic across two logical interfaces that reside on a single physical port. The same-port local switching feature addresses that implementation.
The figure below shows a network that uses local switching for both Frame Relay to Frame Relay and ATM to Frame Relay local switching.
Access Circuit Redundancy Local Switching
The Automatic Protection Switching (APS) mechanism provides a switchover time of less than 50 milliseconds. However, the switchover time is longer in a pseudowire configuration due to the time the pseudowire takes to enter the UP state on switchover. The switchover time of the pseudowire can be eliminated if there is a single pseudowire on the working and protect interfaces instead of separate pseudowire configurations. A single pseudowire also eliminates the need to have Label Distribution Protocols (LDP) negotiations on a switchover. The virtual interface or controller model provides a method to configure a single pseudowire between the provider edge (PE) routers.
Access Circuit Redundancy (ACR) ensures low data traffic downtime by reducing the switchover time. ACR works on the APS 1+1, nonrevertive model where each redundant line pair consists of a working line and a protect line. If a signal fail condition or a signal degrade condition is detected, the hardware switches from the working line to the protect line.
The working and protect interfaces can be on the following:
- Same SPA
- Different SPA but on the same line card
- SPAs on different line cards
When the working or protection interface is configured with ACR, a virtual interface is created and a connection is established between the virtual interfaces to facilitate the switching of data between the interfaces.
ACR for ATM-to-ATM Local Switching
ACR for ATM-to-ATM local switching supports the ATM AAL5 and ATM AAL0 encapsulation types and switches Layer 2 data between L2 transport virtual circuits (VCs).
Note | The L2 transport VCs must be configured with the same encapsulation type. |
The figure below shows the ACR for ATM-to-ATM local switching model.
In the figure:
- ATM 1/0/0 and ATM 9/0/0 are configured as working and protection interfaces of ACR 1 group.
- ATM 7/1/0 and ATM 9/1/0 are configured as working and protection interfaces of ACR 2 group.
- A connection is established between the ACRs.
- The Add/Drop Multiplexer (ADM) sends data to both the interfaces, which are part of the ACR group ACR 1.
- The cells or packets received on the APS active interface VC (0/32) of ACR group 1 are switched to the ACR 2 interface VC (1/32) and the cells or packets from the APS inactive interface are dropped.
- The packets received on the ACR 2 VC (1/32) interface are replicated on both the physical interfaces, which are part of the ACR group ACR 2.
ACR for CEM-to-CEM Local Switching
Circuit Emulation (CEM) transports Time Division Multiplexing (TDM) data over TDM pseudowires, allowing mobile operators to carry TDM traffic over an IP or Multiprotocol Label Switching (MPLS) network. ACR for CEM-to-CEM involves creating a virtual controller and associating the virtual controller with the physical controllers. The virtual controller is created when APS and ACR are configured on the physical controller. All commands executed on the virtual controller apply to the working and protect controller. The virtual controller simplifies the single point of configuration and provides the flexibility of not running a backup pseudowire for the protect controller in the event of a failure. This way there is no switchover between the pseudowires, which in turn reduces the recovery time when the physical link fails.
When the CEM group is configured on the virtual controller, a virtual CEM-ACR interface is created and associated with the CEM circuit. ACR creates CEM interfaces and CEM circuits on the physical interfaces that correspond to the physical controllers belonging to the same ACR group.
The figure below shows the ACR for CEM-to-CEM local switching model:
In the figure:
- Packets are received from the ADM. The packets from the APS inactive interface are dropped and the packets received on the APS active interface are switched.
- The packets received on the CEM circuit ID 1 of the APS active interface, which is part of ACR group 1, are switched to the CEM circuit ID 2 of the APS active interface, which is part of ACR group 2.
- The packets are duplicated and sent on both the APS active and inactive physical CEM interfaces that are part of ACR group 2.
How to Configure Layer 2 Local Switching
For information about Layer 2 local switching on the Cisco 10000 series routers, see the Configuring Layer 2 Local Switching document.
- Configuring ATM-to-ATM PVC Local Switching and Same-Port Switching
- Configuring ATM-to-ATM PVP Local Switching
- Configuring ATM PVP Same-Port Switching
- Configuring ATM-to-Ethernet Port Mode Local Switching
- Configuring ATM-to-Ethernet VLAN Mode Local Switching
- Configuring Ethernet VLAN Same-Port Switching
- Configuring Ethernet Port Mode to Ethernet VLAN Local Switching
- Configuring ATM-to-Frame Relay Local Switching
- Configuring Frame Relay-to-Frame Relay Local Switching
- Configuring Frame Relay Same-Port Switching
- Configuring HDLC Local Switching
- Configuring ACR for ATM-to-ATM Local Switching
- Configuring CEM-to-CEM ACR Local Switching
- Verifying Layer 2 Local Switching
Configuring ATM-to-ATM PVC Local Switching and Same-Port Switching
You can configure local switching for both ATM AAL5 and ATM AAL0 encapsulation types.
Creating the ATM PVC is not required. If you do not create a PVC, one is created for you. For ATM-to-ATM local switching, the autoprovisioned PVC is given the default encapsulation type AAL0 cell relay.
Note | Starting with Cisco IOS Release 12.0(30)S, you can configure same-port switching following the steps in this section. |
1.
enable
2.
configure
terminal
3.
interface
atm
slot/port
4.
pvc
vpi
/
vci
l2transport
5.
encapsulation
layer-type
6.
exit
7.
exit
8.
connect
connection-name
interface
pvc
interface
pvc
DETAILED STEPS
Configuring ATM-to-ATM PVP Local Switching
Perform this task to configure ATM-to-ATM PVP local switching.
Starting with Cisco IOS Release 12.0(30)S, you can configure same-port switching, as detailed in the Configuring ATM PVP Same-Port Switching.
1.
enable
2.
configure
terminal
3.
interface
atm
slot/port
4.
atm
pvp
vpi
l2transport
5.
exit
6.
exit
7.
connect
connection-name
interface
pvp
interface
pvp
DETAILED STEPS
Configuring ATM PVP Same-Port Switching
Perform this task to configure ATM PVP switching on an ATM interface.
1.
enable
2.
configure
terminal
3.
interface
atm
slot/subslot/port
4.
atm
pvp
vpi
l2transport
5.
exit
6.
exit
7.
connect
connection-name
interface
pvp
interface
pvp
DETAILED STEPS
Configuring ATM-to-Ethernet Port Mode Local Switching
For ATM to Ethernet port mode local switching, creating the ATM PVC is not required. If you do not create a PVC, one is created for you. For ATM-to-Ethernet local switching, the autoprovisioned PVC is given the default encapsulation type AAL5SNAP.
ATM-to-Ethernet local switching supports both the IP and Ethernet interworking types. When the Ethernet interworking type is used, the interworking device (router) expects a bridged packet. Therefore, configure the ATM CPE for either IRB or RBE.
Note | Enabling ICMP Router Discovery Protocol on the Ethernet side is recommended. |
ATM-to-Ethernet local switching supports the following encapsulation types:
- ATM-to-Ethernet with IP interworking: AAL5SNAP, AAL5MUX
- ATM-to-Ethernet with Ethernet interworking: AAL5SNAP
Perform this task to configure local switching between ATM and Ethernet port mode.
1.
enable
2.
configure
terminal
3.
interface
atm
slot/port
4.
pvc
vpi
/
vci
l2transport
5.
encapsulation
layer-type
6.
exit
7.
exit
8.
interface
fastethernet
slot
/
subslot
/
port
9.
exit
10.
connect
connection-name
interface
pvc
interface
[interworkingip |
ethernet]
DETAILED STEPS
Configuring ATM-to-Ethernet VLAN Mode Local Switching
For ATM-to-Ethernet VLAN mode local switching, creating the ATM permanent virtual circuit (PVC) is not required. If you do not create a PVC, one is created for you. For ATM-to-Ethernet local switching, the autoprovisioned PVC is given the default encapsulation type as ATM adaptation layer 5 (AAL5) Subnetwork Access Protocol (SNAP).
ATM-to-Ethernet local switching supports both the IP and Ethernet interworking types. When the Ethernet interworking type is used, the interworking device (router) expects a bridged packet. Therefore, configure the ATM customer premises equipment (CPE) for either Integrated Routing and Bridging (IRB) or Routed Bridged Encapsulation (RBE).
Note | Enabling Internet Control Message Protocol (ICMP) Router Discovery Protocol (IRDP) on the Ethernet side is recommended. |
The VLAN header is removed from frames that are received on an Ethernet subinterface.
Note | On the provider edge (PE) router, ensure that the maximum transmission unit (MTU) value of ATM interfaces (default MTU is 4470 bytes) and Gigabit Ethernet interfaces (default MTU is 1500 bytes) is the same. On the customer edge (CE) router, ensure that the MTU value of ATM and Gigabit Ethernet interfaces is at least 14 bytes less than the MTU value of the respective interfaces on the PE router during ATM-to-Ethernet VLAN mode local switching. |
Perform this task to configure local switching for ATM to Ethernet in VLAN mode.
1.
enable
2.
configure
terminal
3.
interface
atm
slot/subslot/port
4.
pvc
vpi/vci
l2transport
5.
encapsulation
layer-type
6.
exit
7.
interface
fastethernet
slot/port.subinterface-number
8.
encapsulation
dot1q
vlan-id
9.
exit
10.
connect
connection-name
interface
pvc
interface
[interworking
ip |
ethernet]
DETAILED STEPS
Configuring Ethernet VLAN Same-Port Switching
1.
enable
2.
configure
terminal
3.
interface
fastethernet
slot/port.subinterface-number
4.
encapsulation
dot1q
vlan-id
5.
exit
6.
interface
fastethernet
slot
/
port.subinterface-number
7.
encapsulation
dot1q
vlan-id
8.
exit
9.
connect
connection-name
interface
interface
DETAILED STEPS
Configuring Ethernet Port Mode to Ethernet VLAN Local Switching
1.
enable
2.
configure
terminal
3.
interface
fastethernet
slot/subslot/port
4.
interface
fastethernet
slot/port/subinterface-number
5.
encapsulation
dot1q
vlan-id
6.
exit
7.
connect
connection-name
interface
interface
[interworking
ip |
ethernet]
DETAILED STEPS
Configuring ATM-to-Frame Relay Local Switching
You use the interworking ip keywords for configuring ATM-to-Frame Relay local switching.
FRF.8 Frame Relay-to-ATM service interworking functionality is not supported. Frame Relay discard-eligible (DE) bits do not get mapped to ATM cell loss priority (CLP) bits, and forward explicit congestion notification (FECN) bits do not get mapped to ATM explicit forward congestion indication (EFCI) bits.
Creating the PVC is not required. If you do not create a PVC, one is created for you. For ATM-to-Ethernet local switching, the automatically provisioned PVC is given the default encapsulation type AAL5SNAP.
ATM-to-Frame Relay local switching supports the following encapsulation types:
1.
enable
2.
configure
terminal
3.
interface
atm
slot/port
4.
pvc
vpi/vci
l2transport
5.
encapsulation
layer-type
6.
exit
7.
interface
serial
slot/subslot/port
8.
encapsulation
frame-relay
[cisco |
ietf]
9.
frame-relay
interface-dlci
dlci
switched
10.
exit
11.
connect
connection-name
interface
pvc
interface
dlci
[interworking
ip |
ethernet]
DETAILED STEPS
Configuring Frame Relay-to-Frame Relay Local Switching
For information on Frame Relay-to-Frame Relay Local Switching, see the Distributed Frame Relay Switching feature module.
With Cisco IOS Release 12.0(30)S, you can switch between virtual circuits on the same port, as detailed in the Configuring Frame Relay Same-Port Switching.
1.
enable
2.
configure
terminal
3.
ip
cef
distributed
4.
frame-relay
switching
5.
interface
type
number
6.
encapsulation
frame-relay
[cisco |
ietf]
7.
frame-relay
interface-dlci
dlci
switched
8.
exit
9.
exit
10.
connect
connection-name
interface
dlci
interface
dlci
DETAILED STEPS
Configuring Frame Relay Same-Port Switching
Perform this task to configure Frame Relay switching on the same interface.
1.
enable
2.
configure
terminal
3.
ip
cef
[distributed]
4.
frame-relay
switching
5.
interface
type
number
6.
encapsulation
frame-relay
[cisco |
ietf]
7.
frame-relay
intf-type
[dce|
dte|
nni]
8.
frame-relay
interface-dlci
dlci
switched
9.
exit
10.
exit
11.
connect
connection-name
interface
dlci
interface
dlci
DETAILED STEPS
Configuring HDLC Local Switching
Perform this task to configure local switching for HDLC. The PE routers are configured with HDLC encapsulation. The CE routers are configured with any HDLC-based encapsulation, including HDLC, PPP, and Frame Relay.
- Ensure that the interfaces you configure for HDLC encapsulation can handle ping packets that are smaller, the same size as, or larger than the CE interface MTU.
- Enable Cisco Express Forwarding.
1.
enable
2.
configure
terminal
3.
ip
cef
4.
interface
type
number
5.
exit
6.
connect
connection-name
interface
interface
DETAILED STEPS
Configuring ACR for ATM-to-ATM Local Switching
Note | The connect command provides an infrastructure to create the required L2 transport VCs with the default AAl0 encapsulation type and does not require that the VCs must exist. |
1.
enable
2.
configure
terminal
3.
interface
atm
slot/subslot/port
4.
aps
group
[acr]
group-number
5.
aps
working
circuit-number
6.
aps
protect
circuit-number
ip-address
7.
exit
8.
interface
acr
acr-group-number
9.
pvc
[name]
vpi/vci
l2transport
10.
exit
11.
exit
12.
connect
connection-name
type
number
pvc
type
number
pvc
DETAILED STEPS
Configuring CEM-to-CEM ACR Local Switching
Perform this task to configure ACR for CEM-to-CEM local switching.
1.
enable
2.
configure
terminal
3.
controller
sonet
slot/subslot/port
4.
aps
group
[acr]
group-number
5.
aps
working
circuit-number
6.
aps
protect
circuit-number
ip-address
7.
exit
8.
controller
sonet-acr
acr-group-number
9.
framing
sonet
10.
sts-1
number
11.
mode
vt-15
12.
vtg
number
t1
number
cem-group
number
timeslots
number
13.
exit
14.
exit
15.
interface
cem-acr
acr-group-number
16.
exit
17.
cem
slot/port/channel
18.
xconnect
virtual-connect-id
19.
exit
20.
exit
21.
connect
connection-name
type
number
circuit-id
type
number
circuit-id
DETAILED STEPS
Verifying Layer 2 Local Switching
- Verifying Layer 2 Local Switching Configuration
- Verifying the NSF SSO Local Switching Configuration
- Troubleshooting Tips
Verifying Layer 2 Local Switching Configuration
To verify configuration of the Layer 2 Local Switching feature, use the following commands on the provider edge (PE) router:
1.
show
connection
[all |
element |
id
id |
name
name |
port
port]
2.
show
atm
pvc
3.
show
frame-relay
pvc
[pvc]
DETAILED STEPS
Verifying the NSF SSO Local Switching Configuration
Layer 2 local switching provides NSF/SSO support for Local Switching of the following attachment circuits on the same router:
For information about configuring NSF/SSO on the RPs, see the Stateful Switchover feature module. To verify that the NSF/SSO: Layer 2 Local Switching is working correctly, follow the steps in this section.
1. Issue the pingcommand or initiate traffic between the two CE routers.
2. Force the switchover from the active RP to the standby RP by using the redundancy force-switchover command. This manual procedure allows for a "graceful" or controlled shutdown of the active RP and switchover to the standby RP. This graceful shutdown allows critical cleanup to occur.
3. Issue the show connect all command to ensure that the Layer 2 local switching connection on the dual RP is operating.
4. Issue the ping command from the CE router to verify that the contiguous packet outage was minimal during the switchover.
DETAILED STEPS
Troubleshooting Tips
You can troubleshoot Layer 2 local switching using the following commands on the PE router:
Configuration Examples for Layer 2 Local Switching
- Example: ATM-to-ATM Local Switching
- Example: ATM PVC Same-Port Switching
- Example: Configuring ATM PVP Same-Port Switching
- Example: ATM-to-Ethernet Local Switching
- Example: Ethernet VLAN Same-Port Switching
- Example: ATM-to-Frame Relay Local Switching
- Example: Frame Relay-to-Frame Relay Local Switching
- Example: Frame Relay DLCI Same-Port Switching
- Example: HDLC Local Switching
- Example: NSF SSO Ethernet Port Mode to Ethernet VLAN Local Switching
Example: ATM-to-ATM Local Switching
The following example shows local switching on ATM interfaces configured for AAL5:
interface atm1/0/0 pvc 0/100 l2transport encapsulation aal5 interface atm2/0/0 pvc 0/100 l2transport encapsulation aal5 connect aal5-conn atm1/0/0 0/100 atm2/0/0 0/100
Example: ATM PVC Same-Port Switching
The following example shows same-port switching between two PVCs on one ATM interface:
interface atm1/0/0 pvc 0/100 l2transport encapsulation aal5 pvc 0/200 l2transport encapsulation aal5 connect conn atm1/0/0 0/100 atm1/0/0 0/200
Example: Configuring ATM PVP Same-Port Switching
The following example shows same-port switching between two PVPs on one ATM interface:
interface atm1/0/0 atm pvp 100 l2transport atm pvp 200 l2transport connect conn atm1/0/0 100 atm1/0/0 200
Example: ATM-to-Ethernet Local Switching
ATM-to-Ethernet local switching terminates an ATM frame to an Ethernet/VLAN frame over the same PE router. Two interworking models are used: Ethernet mode and IP mode.
- Example: ATM-to-Ethernet VLAN Mode Local Switching
- Example: ATM-to-Ethernet Port Mode Local Switching
Example: ATM-to-Ethernet VLAN Mode Local Switching
The following example shows an Ethernet interface configured for Ethernet VLAN, and an ATM PVC interface configured for AAL5 encapsulation. The connect command allows local switching between these two interfaces and specifies the interworking type as Ethernet mode.
Note | On the provider edge (PE) router, ensure that the maximum transmission unit (MTU) value of ATM (default MTU is 4470 bytes) and GigabitEthernet (default MTU is 1500 bytes) interfaces is the same. On the customer edge (CE) router, ensure that the MTU value of ATM and GigabitEthernet interfaces is at least 14 bytes less than the MTU value of the respective interfaces on the PE router during ATM-to-Ethernet VLAN mode local switching. |
interface fastethernet6/0/0.1 encapsulation dot1q 10 interface atm2/0/0 pvc 0/400 l2transport encapsulation aal5 connect atm-ethvlan-con atm2/0/0 0/400 fastethernet6/0/0.1 interworking ethernet
Example: ATM-to-Ethernet Port Mode Local Switching
The following example shows an Ethernet interface configured for Ethernet and an ATM interface configured for AAL5SNAP encapsulation. The connect command allows local switching between these two interfaces and specifies the interworking type as IP mode.
interface atm0/0/0 pvc 0/100 l2transport encapsulation aal5snap interface fastethernet6/0/0 connect atm-eth-con atm0/0/0 0/100 fastethernet6/0/0 interworking ip
Example: Ethernet VLAN Same-Port Switching
The following example shows same-port switching between two VLANs on one Ethernet interface:
interface fastethernet0/0.1 encapsulation dot1q 1 interface fastethernet0/0.2 encapsulation dot1q 2 connect conn FastEthernet0/0.1 FastEthernet0/0.2
Example: ATM-to-Frame Relay Local Switching
The following example shows a serial interface configured for Frame Relay and an ATM interface configured for AAL5SNAP encapsulation. The connect command allows local switching between these two interfaces.
interface serial1/0 encapsulation frame-relay interface atm1/0 pvc 7/100 l2transport encapsulation aal5snap connect atm-fr-conn atm1/0 7/100 serial1/0 100 interworking ip
Example: Frame Relay-to-Frame Relay Local Switching
The following example shows serial interfaces configured for Frame Relay. The connect command allows local switching between these two interfaces.
frame-relay switching ip cef distributed interface serial3/0/0 encapsulation frame-relay frame-relay interface-dlci 100 switched frame-relay intf-type dce interface serial3/1/0 encapsulation frame-relay ietf frame-relay interface-dlci 200 switched frame-relay intf-type dce connect fr-con serial3/0/0 100 serial3/1/0 200
Example: Frame Relay DLCI Same-Port Switching
The following example shows same-port switching between two data links on one Frame Relay interface:
interface serial1/0 encapsulation frame-relay frame-relay int-type nni connect conn serial1/0 100 serial1/0 200
Example: HDLC Local Switching
The following example shows local switching of two serial interfaces for HDLC:
interface serial1/0 no ip address interface serial2/0 no ip address connect conn1 serial1/0 serial1/0
Example: NSF SSO Ethernet Port Mode to Ethernet VLAN Local Switching
The following configuration uses the network topology shown in the figure below.
The following example shows the configuration of the CE interfaces to connect to the PE1 router:
|
CE1 |
CE2 |
|---|---|
ip routing ! interface fa3/1/0 description: connection to PE fa1/1/1 no shutdown ip address 10.1.1.1 255.255.255.0 |
ip routing ! interface fa4/0 no shutdown ! interface fa4/0.1 description: connection to PE1 fa6/0/0.1 encapsulation dot1Q 10 ip address 10.1.1.2 255.255.255.0 ! interface fa4/0.2 description - connection to PE1 fa6/0/0.2 encapsulation dot1Q 20 ip address 172.16.1.2 255.255.255.0 |
The following example shows the configuration of the PE1 router with NSF/SSO and the PE interfaces to the CE routers:
|
PE1 |
|---|
redundancy no keepalive-enable mode sso ! hw-module slot 2 image disk0:rsp-pv-mz.shaft.111004 hw-module slot 3 image disk0:rsp-pv-mz.shaft.111004 ! ip routing ip cef distributed ! interface fa1/1/1 description - connection to CE1 fa3/1/0 no shutdown no ip address ! interface fa4/0/0 description - connection to CE3 fa6/0 no shutdown no ip address ! interface fa6/0/0 no shutdown no ip address ! interface fa6/0/0.1 description - connection to CE2 fa4/0.1 encapsulation dot1Q 10 no ip address ! interface fa6/0/0.2 description - connection to CE2 fa4/0.2 encapsulation dot1Q 20 no ip address |
The following example shows the configuration of ICMP Router Discovery Protocol (IRDP) on the CE router for Interworking IP for ARP mediation:
|
CE1 |
CE2 |
|---|---|
interface FastEthernet3/1/0 ip irdp ip irdp maxadvertinterval 0 |
interface FastEthernet4/0.1 ip irdp ip irdp maxadvertinterval 0 |
The following example shows the configuration of OSPF on the CE routers:
|
CE1 |
CE2 |
|---|---|
interface loopback 1 ip address 10.11.11.11 255.255.255.255 ! router ospf 10 network 10.11.11.11 0.0.0.0 area 0 network 192.168.1.1 0.0.0.0 area 0 |
interface loopback 1 ip address 12.12.12.12 255.255.255.255 ! router ospf 10 network 10.12.12.12 0.0.0.0 area 0 network 192.168.1.2 0.0.0.0 area 0 |
The following example shows the configuration of local switching on the PE1 router for interworking Ethernet:
connect eth-vlan1 fa1/1/1 fa6/0/0.1 interworking ethernet connect eth-vlan2 fa4/0/0 fa6/0/0.2 interworking ethernet
The following example shows the configuration of local switching on the PE1 router for interworking IP:
connect eth-vlan1 fa1/1/1 fa6/0/0.1 interworking ip connect eth-vlan2 fa4/0/0 fa6/0/0.2 interworking ip
Additional References for Layer 2 Local Switching
Related Documents
|
Related Topic |
Document Title |
|---|---|
|
MPLS |
MPLS Product Literature |
|
Layer 2 local switching configuration tasks |
|
|
Frame Relay-ATM interworking configuration tasks |
Configuring Frame Relay-ATM Interworking |
|
Frame Relay-to-Frame Relay local switching configuration tasks |
Distributed Frame Relay Switching |
|
CEoP and Channelized ATM SPAs on Cisco 7600 series router configuration tasks |
Standards and RFCs
|
Standard/RFC |
Title |
|---|---|
|
draft-ietf-l2tpext-l2tp-base-03.txt |
Layer Two Tunneling Protocol (Version 3) 'L2TPv3' |
|
draft-martini-l2circuit-encap-mpls-04.txt |
Encapsulation Methods for Transport of Layer 2 Frames Over IP and MPLS Networks |
|
draft-martini-l2circuit-trans-mpls-09.txt |
Transport of Layer 2 Frames Over MPLS |
|
draft-ietf-ppvpn-l2vpn-00.txt |
An Architecture for L2VPNs |
Technical Assistance
|
Description |
Link |
|---|---|
|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for Layer 2 Local Switching
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.