- Read Me First
- Cisco BGP Overview
- BGP 4
- Configuring a Basic BGP Network
- BGP 4 Soft Configuration
- BGP Support for 4-byte ASN
- IPv6 Routing: Multiprotocol BGP Extensions for IPv6
- IPv6 Routing: Multiprotocol BGP Link-Local Address Peering
- IPv6 Multicast Address Family Support for Multiprotocol BGP
- Configuring Multiprotocol BGP (MP-BGP) Support for CLNS
- BGP IPv6 Admin Distance
- Connecting to a Service Provider Using External BGP
- BGP Route-Map Continue
- BGP Route-Map Continue Support for Outbound Policy
- Removing Private AS Numbers from the AS Path in BGP
- Configuring BGP Neighbor Session Options
- BGP Neighbor Policy
- BGP Dynamic Neighbors
- BGP Support for Next-Hop Address Tracking
- BGP Restart Neighbor Session After Max-Prefix Limit Reached
- BGP Support for Dual AS Configuration for Network AS Migrations
- Configuring Internal BGP Features
- BGP VPLS Auto Discovery Support on Route Reflector
- BGP FlowSpec Route-reflector Support
- BGP Flow Specification Client
- BGP NSF Awareness
- BGP Graceful Restart per Neighbor
- BGP Support for BFD
- IPv6 NSF and Graceful Restart for MP-BGP IPv6 Address Family
- BGP Persistence
- BGP Link Bandwidth
- Border Gateway Protocol Link-State
- iBGP Multipath Load Sharing
- BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS-VPN
- Loadsharing IP Packets over More Than Six Parallel Paths
- BGP Policy Accounting
- BGP Policy Accounting Output Interface Accounting
- BGP Cost Community
- BGP Support for IP Prefix Import from Global Table into a VRF Table
- BGP Support for IP Prefix Export from a VRF Table into the Global Table
- BGP per Neighbor SoO Configuration
- Per-VRF Assignment of BGP Router ID
- BGP Next Hop Unchanged
- BGP Support for the L2VPN Address Family
- BGP Event-Based VPN Import
- BGP Best External
- BGP PIC Edge for IP and MPLS-VPN
- Detecting and Mitigating a BGP Slow Peer
- Configuring BGP: RT Constrained Route Distribution
- Configuring a BGP Route Server
- BGP Diverse Path Using a Diverse-Path Route Reflector
- BGP Enhanced Route Refresh
- Configuring BGP Consistency Checker
- BGP—Origin AS Validation
- BGP MIB Support
- BGP 4 MIB Support for Per-Peer Received Routes
- BGP Support for Nonstop Routing (NSR) with Stateful Switchover (SSO) Using L2VPN VPLS
- BGP Support for Nonstop Routing (NSR) with Stateful Switchover (SSO) Using L2VPN VPLS
- BGP NSR Auto Sense
- BGP NSR Support for iBGP Peers
- BGP Graceful Shutdown
- BGP — mVPN BGP sAFI 129 - IPv4
- BGP-MVPN SAFI 129 IPv6
- BFD—BGP Multihop Client Support, cBit (IPv4 and IPv6), and Strict Mode
- BGP Attribute Filter and Enhanced Attribute Error Handling
- BGP Additional Paths
- BGP-Multiple Cluster IDs
- BGP-VPN Distinguisher Attribute
- BGP-RT and VPN Distinguisher Attribute Rewrite Wildcard
- VPLS BGP Signaling
- Multicast VPN BGP Dampening
- BGP—IPv6 NSR
- BGP-VRF-Aware Conditional Advertisement
- BGP—Selective Route Download
- BGP—Support for iBGP Local-AS
- eiBGP Multipath for Non-VRF Interfaces (IPv4/IPv6)
- L3VPN iBGP PE-CE
- BGP NSR Support for MPLS VPNv4 and VPNv6 Inter-AS Option B
- BGP-RTC for Legacy PE
- BGP PBB EVPN Route Reflector Support
- BGP Monitoring Protocol
- VRF Aware BGP Translate-Update
- BGP Support for MTR
- BGP Accumulated IGP
- BGP MVPN Source-AS Extended Community Filtering
- BGP AS-Override Split-Horizon
- BGP Support for Multiple Sourced Paths Per Redistributed Route
- Maintenance Function: BGP Routing Protocol
- Finding Feature Information
- Prerequisites for BGP per Neighbor SoO Configuration
- Restrictions for BGP per Neighbor SoO Configuration
- Information About Configuring BGP per Neighbor SoO
- How to Configure BGP per Neighbor SoO
- Configuration Examples for BGP per Neighbor SoO Configuration
- Where to Go Next
- Additional References
- Feature Information for BGP per Neighbor SoO Configuration
BGP per Neighbor SoO Configuration
The BGP per Neighbor SoO Configuration feature simplifies the configuration of the site-of-origin (SoO) value. Per neighbor SoO configuration introduces two new commands that can be configured in submodes under router configuration mode to set the SoO value.
- Finding Feature Information
- Prerequisites for BGP per Neighbor SoO Configuration
- Restrictions for BGP per Neighbor SoO Configuration
- Information About Configuring BGP per Neighbor SoO
- How to Configure BGP per Neighbor SoO
- Configuration Examples for BGP per Neighbor SoO Configuration
- Where to Go Next
- Additional References
- Feature Information for BGP per Neighbor SoO Configuration
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 BGP per Neighbor SoO Configuration
This feature assumes that a Border Gateway Protocol (BGP) network is configured and that Cisco Express Forwarding is enabled in your network.
Restrictions for BGP per Neighbor SoO Configuration
A BGP neighbor or peer policy template-based SoO configuration takes precedence over the SoO value configured in an inbound route map.
Information About Configuring BGP per Neighbor SoO
Site of Origin BGP Community Attribute
The site-of-origin (SoO) extended community is a BGP extended community attribute that is used to identify routes that have originated from a site so that the readvertisement of that prefix back to the source site can be prevented. The SoO extended community uniquely identifies the site from which a router has learned a route. BGP can use the SoO value associated with a route to prevent routing loops.
Route Distinguisher
A route distinguisher (RD) creates routing and forwarding tables and specifies the default route distinguisher for a VPN. The RD is added to the beginning of an IPv4 prefix to change it into a globally unique VPN-IPv4 prefix. An RD can be composed in one of two ways: with an autonomous system number and an arbitrary number or with an IP address and an arbitrary number.
You can enter an RD in either of these formats:
Enter a 16-bit autonomous system number, a colon, and a 32-bit number. For example:
45000:3
Enter a 32-bit IP address, a colon, and a 16-bit number. For example:
192.168.10.15:1
BGP per Neighbor Site of Origin Configuration
There are three ways to configure an SoO value for a BGP neighbor:
BGP peer policy template--A peer policy template is created, and an SoO value is configured as part of the peer policy. Under address family IPv4 VRF, a neighbor is identified and is configured to inherit the peer policy that contains the SoO value.
BGP neighbor command--Under address family IPv4 VRF, a neighbor is identified, and an SoO value is configured for the neighbor.
BGP peer group--Under address family IPv4 VRF, a BGP peer group is configured, an SoO value is configured for the peer group, a neighbor is identified, and the neighbor is configured as a member of the peer group.
Note | A BGP neighbor or peer policy template-based SoO configuration takes precedence over the SoO value configured in an inbound route map. |
The configuration of SoO values for BGP neighbors is performed on a provider edge (PE) router, which is the VPN entry point. When SoO is enabled, the PE router forwards prefixes to the customer premises equipment (CPE) only when the SoO tag of the prefix does not match the SoO tag configured for the CPE.
For example, in the figure below, an SoO tag is set as 65000:1 for the customer site that includes routers CPE1 and CPE2 with an autonomous system number of 65000. When CPE1 sends prefixes to PE1, PE1 tags the prefixes with 65000:1, which is the SoO tag for CPE1 and CPE2. When PE1 sends the tagged prefixes to PE2, PE2 performs a match against the SoO tag from CPE2. Any prefixes with the tag value of 65000:1 are not sent to CPE2 because the SoO tag matches the SoO tag of CPE2, and a routing loop is avoided.
Benefits of BGP per Neighbor Site of Origin
In releases prior to the introduction of this feature, the SoO extended community attribute is configured using an inbound route map that sets the SoO value during the update process. With the introduction of the BGP per Neighbor Site of Origin feature, two new commands configured in submodes under router configuration mode simplify the SoO value configuration.
BGP Peer Policy Templates
Peer policy templates are used to configure BGP policy commands that are configured for neighbors that belong to specific address families. Peer policy templates are configured once and then applied to many neighbors through the direct application of a peer policy template or through inheritance from peer policy templates. The configuration of peer policy templates simplifies the configuration of BGP policy commands that are applied to all neighbors within an autonomous system.
Peer policy templates support inheritance. A directly applied peer policy template can directly or indirectly inherit configurations from up to seven peer policy templates. So, a total of eight peer policy templates can be applied to a neighbor or neighbor group.
The configuration of peer policy templates simplifies and improves the flexibility of BGP configuration. A specific policy can be configured once and referenced many times. Because a peer policy supports up to eight levels of inheritance, very specific and very complex BGP policies can be created.
For more details about BGP peer policy templates, see the "Configuring a Basic BGP Network" module.
How to Configure BGP per Neighbor SoO
Enabling Cisco Express Forwarding and Configuring VRF Instances
Perform this task on both of the PE routers in the figure above to configure Virtual Routing and Forwarding (VRF) instances to be used with the per-VRF assignment tasks. In this task, Cisco Express Forwarding is enabled, and a VRF instance named SOO_VRF is created. To make the VRF functional, a route distinguisher is created, and the VRF is associated with an interface. When the route distinguisher is created, the routing and forwarding tables are created for the VRF instance named SOO_VRF. After associating the VRF with an interface, the interface is configured with an IP address.
1.
enable
2.
configure
terminal
3.
ip
cef
4.
ip
vrf
vrf-name
5.
rd
route-distinguisher
6.
route-target
{export |
both}
route-target-ext-community
7.
route-target
{import |
both}
route-target-ext-community
8.
exit
9.
interface
type
number
10.
ip
vrf
forwarding
vrf-name
[downstream
vrf-name2]
11.
ip
address
ip-address
mask
[secondary]
12.
end
13.
show
ip
vrf
[brief |
detail |
interfaces |
id] [vrf-name] [output-modifiers]
DETAILED STEPS
Examples
The following output of the show ip vrf command displays the VRF named SOO_VRF configured in this task.
Device# show ip vrf Name Default RD Interfaces SOO_VRF 1:1 GE1/0/0
Configuring a per Neighbor SoO Value Using a BGP Peer Policy Template
Perform this task on router PE1 in the figure above to configure an SoO value for a BGP neighbor at the router CPE1 in the figure above using a peer policy template. In this task, a peer policy template is created, and the SoO value is configured for the peer policy. Under address family IPv4 VRF, a neighbor is identified and is configured to inherit the peer policy that contains the SoO value.
If a BGP peer inherits from several peer policy templates that specify different SoO values, the SoO value in the last template applied takes precedence and is applied to the peer. However, direct configuration of the SoO value on the BGP neighbor overrides any inherited template configurations of the SoO value.
This task assumes that the task described in the Enabling Cisco Express Forwarding and Configuring VRF Instances has been performed.
Note | A BGP peer cannot inherit from a peer policy or session template and be configured as a peer group member at the same. BGP templates and BGP peer groups are mutually exclusive. > |
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
template
peer-policy
policy-template-name
5.
soo
extended-community-value
6.
exit-peer-policy
7.
address-family
ipv4
[unicast |
multicast|
vrf
vrf-name]
8.
neighbor
ip-address
remote-as
autonomous-system-number
9.
neighbor
ip-address
activate
10.
neighbor
ip-address
inherit
peer-policy
policy-template-name
11.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable
Example: Router> enable |
Enables privileged EXEC mode. |
Step 2 |
configure
terminal
Example: Router# configure terminal |
Enters global configuration mode. |
Step 3 |
router
bgp
autonomous-system-number
Example: Router(config)# router bgp 50000 |
Enters router configuration mode for the specified routing process. |
Step 4 |
template
peer-policy
policy-template-name
Example: Router(config-router)# template peer-policy SOO_POLICY |
Creates a peer policy template and enters policy-template configuration mode. |
Step 5 |
soo
extended-community-value
Example: Router(config-router-ptmp)# soo 65000:1 |
Sets the SoO value for a BGP peer policy template. |
Step 6 |
exit-peer-policy
Example: Router(config-router-pmtp)# exit-peer-policy |
Exits policy-template configuration mode and returns to router configuration mode. |
Step 7 |
address-family
ipv4
[unicast |
multicast|
vrf
vrf-name]
Example: Router(config-router)# address-family ipv4 vrf SOO_VRF |
Specifies the IPv4 address family and enters address family configuration mode.
|
Step 8 |
neighbor
ip-address
remote-as
autonomous-system-number
Example: Router(config-router-af)# neighbor 192.168.1.1 remote-as 65000 |
Adds the IP address of the neighbor in the specified autonomous system to the IPv4 multiprotocol BGP neighbor table of the local router. |
Step 9 |
neighbor
ip-address
activate
Example: Router(config-router-af)# neighbor 192.168.1.1 activate |
Enables the neighbor to exchange prefixes for the IPv4 VRF address family with the local router. |
Step 10 |
neighbor
ip-address
inherit
peer-policy
policy-template-name
Example: Router(config-router-af)# neighbor 192.168.1.1 inherit peer-policy SOO_POLICY |
Sends a peer policy template to a neighbor so that the neighbor can inherit the configuration.
|
Step 11 |
end
Example: Router(config-router-af)# end |
Exits address family configuration mode and returns to privileged EXEC mode. |
Configuring a per Neighbor SoO Value Using a BGP neighbor Command
Perform this task on router PE2 in the figure above to configure an SoO value for the BGP neighbor at router CPE2 in the figure above using a neighbor command. For the IPv4 VRF address family, a neighbor is identified, and an SoO value is configured for the neighbor.
Direct configuration of the SoO value on a BGP neighbor overrides any inherited peer policy template configurations of the SoO value.
This task assumes that the task described in the “Verifying CEF and Configuring VRF Instances” section has been performed with appropriate changes to interfaces and IP addresses.
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
address-family
ipv4
[unicast |
multicast |
vrf
vrf-name]
5.
neighbor
{ip-address |
peer-group-name}
remote-as
autonomous-system-number
6.
neighbor
ip-address
activate
7.
neighbor
{ip-address |
peer-group-name}
soo
extended-community-value
8.
end
DETAILED STEPS
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
enable
Example: Device> enable |
Enables privileged EXEC mode. | ||
Step 2 |
configure
terminal
Example: Device# configure terminal |
Enters global configuration mode. | ||
Step 3 |
router
bgp
autonomous-system-number
Example: Device(config)# router bgp 50000 |
Enters router configuration mode for the specified routing process. | ||
Step 4 |
address-family
ipv4
[unicast |
multicast |
vrf
vrf-name]
Example: Device(config-router)# address-family ipv4 vrf SOO_VRF |
Specifies the IPv4 address family and enters address family configuration mode.
| ||
Step 5 |
neighbor
{ip-address |
peer-group-name}
remote-as
autonomous-system-number
Example: Device(config-router-af)# neighbor 192.168.2.1 remote-as 65000 |
Adds the IP address of the neighbor in the specified autonomous system to the IPv4 multiprotocol BGP neighbor table of the local router. | ||
Step 6 |
neighbor
ip-address
activate
Example: Device(config-router-af)# neighbor 192.168.2.1 activate |
Enables the neighbor to exchange prefixes for the IPv4 VRF address family with the local router.
| ||
Step 7 |
neighbor
{ip-address |
peer-group-name}
soo
extended-community-value
Example: Device(config-router-af)# neighbor 192.168.2.1 soo 65000:1 |
Sets the site-of-origin (SoO) value for a BGP neighbor or peer group. | ||
Step 8 |
end
Example: Device(config-router-af)# end |
Exits address family configuration mode and returns to privileged EXEC mode. |
Configuring a per Neighbor SoO Value Using a BGP Peer Group
Perform this task on router PE1 in the figure above to configure an SoO value for the BGP neighbor at router CPE1 in the figure above using a neighbor command with a BGP peer group. Under address family IPv4 VRF, a BGP peer group is created and an SoO value is configured using a BGP neighbor command, and a neighbor is then identified and added as a peer group member. A BGP peer group member inherits the configuration associated with a peer group, which in this example, includes the SoO value.
Direct configuration of the SoO value on a BGP neighbor overrides any inherited peer group configurations of the SoO value.
This task assumes that the task described in “Enabling Cisco Express Forwarding and Configuring VRF Instances” has been performed.
Note | A BGP peer cannot inherit from a peer policy or session template and be configured as a peer group member at the same. BGP templates and BGP peer groups are mutually exclusive. |
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
address-family
ipv4
[unicast |
multicast |
vrf
vrf-name]
5.
neighbor
peer-group-name
peer-group
6.
neighbor
{ip-address |
peer-group-name}
soo
extended-community-value
7.
neighbor
ip-address
remote-as
autonomous-system-number
8.
neighbor
ip-address
activate
9.
neighbor
ip-address
peer-group
peer-group-name
10.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable
Example: Device> enable |
Enables privileged EXEC mode. |
Step 2 |
configure
terminal
Example: Device# configure terminal |
Enters global configuration mode. |
Step 3 |
router
bgp
autonomous-system-number
Example: Device(config)# router bgp 50000 |
Enters router configuration mode for the specified routing process. |
Step 4 |
address-family
ipv4
[unicast |
multicast |
vrf
vrf-name]
Example: Device(config-router)# address-family ipv4 vrf SOO_VRF |
Specifies the IPv4 address family and enters address family configuration mode.
|
Step 5 |
neighbor
peer-group-name
peer-group
Example: Device(config-router-af)# neighbor SOO_group peer-group |
Creates a BGP peer group. |
Step 6 |
neighbor
{ip-address |
peer-group-name}
soo
extended-community-value
Example: Device(config-router-af)# neighbor SOO_group soo 65000:1 |
Sets the site-of-origin (SoO) value for a BGP neighbor or peer group. |
Step 7 |
neighbor
ip-address
remote-as
autonomous-system-number
Example: Device(config-router-af)# neighbor 192.168.1.1 remote-as 65000 |
Adds the IP address of the neighbor in the specified autonomous system to the IPv4 multiprotocol BGP neighbor table of the local router. |
Step 8 |
neighbor
ip-address
activate
Example: Device(config-router-af)# neighbor 192.168.1.1 activate |
Enables the neighbor to exchange prefixes for the IPv4 VRF address family with the local router. |
Step 9 |
neighbor
ip-address
peer-group
peer-group-name
Example: Device(config-router-af)# neighbor 192.168.1.1 peer-group SOO_group |
Assigns the IP address of a BGP neighbor to a peer group. |
Step 10 |
end
Example: Device(config-router-af)# end |
Exits address family configuration mode and returns to privileged EXEC mode. |
Configuration Examples for BGP per Neighbor SoO Configuration
Example: Configuring a per Neighbor SoO Value Using a BGP Peer Policy Template
The following example shows how to create a peer policy template and configure an SoO value as part of the peer policy. After enabling Cisco Express Forwarding and configuring a VRF instance named SOO_VRF, a peer policy template is created and an SoO value is configured as part of the peer policy. Under the IPv4 VRF address family, a neighbor is identified and configured to inherit the peer policy that contains the SoO value.
ip cef ip vrf SOO_VRF rd 1:1 route-target export 1:1 route-target import 1:1 exit interface GigabitEthernet 1/0/0 ip vrf forwarding SOO_VRF ip address 192.168.1.2 255.255.255.0 exit router bgp 50000 template peer-policy SOO_POLICY soo 65000:1 exit-peer-policy address-family ipv4 vrf SOO_VRF neighbor 192.168.1.1 remote-as 65000 neighbor 192.168.1.1 activate neighbor 192.168.1.1 inherit peer-policy SOO_POLICY end
Example: Configuring a per Neighbor SoO Value Using a BGP neighbor Command
The following example shows how to configure an SoO value for a BGP neighbor. After enabling Cisco Express Forwarding and configuring a VRF instance named SOO_VRF, a neighbor is identified in the IPv4 VRF address family and an SoO value is configured for the neighbor.
ip cef ip vrf SOO_VRF rd 1:1 route-target export 1:1 route-target import 1:1 exit interface GigabitEthernet 1/0/0 ip vrf forwarding SOO_VRF ip address 192.168.2.2 255.255.255.0 exit router bgp 50000 address-family ipv4 vrf SOO_VRF neighbor 192.168.2.1 remote-as 65000 neighbor 192.168.2.1 activate neighbor 192.168.2.1 soo 65000:1 end
Example: Configuring a per Neighbor SoO Value Using a BGP Peer Group
The following example shows how to configure an SoO value for a BGP peer group. After enabling Cisco Express Forwarding and configuring a VRF instance named SOO_VRF, a BGP peer group is configured in the IPv4 VRF address family, an SoO value is configured for the peer group, a neighbor is identified, and the neighbor is configured as a member of the peer group.
ip cef ip vrf SOO_VRF rd 1:1 route-target export 1:1 route-target import 1:1 exit interface GigabitEthernet 1/0/0 ip vrf forwarding SOO_VRF ip address 192.168.1.2 255.255.255.0 exit router bgp 50000 address-family ipv4 vrf SOO_VRF neighbor SOO_GROUP peer-group neighbor SOO_GROUP soo 65000:65 neighbor 192.168.1.1 remote-as 65000 neighbor 192.168.1.1 activate neighbor 192.168.1.1 peer-group SOO_GROUP end
Where to Go Next
To read an overview of BGP, proceed to the "Cisco BGP Overview" module.
To perform basic BGP feature tasks, proceed to the "Configuring a Basic BGP Network" module.
To perform advanced BGP feature tasks, proceed to the "Configuring Advanced BGP Features" module.
To configure BGP neighbor session options, proceed to the "Configuring BGP Neighbor Session Options" module.
To perform internal BGP tasks, proceed to the "Configuring Internal BGP Features" module.
Additional References
Related Documents
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
BGP commands |
|
IP Switching commands |
MIBs
MIB |
MIBs Link |
---|---|
— |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
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 BGP per Neighbor SoO Configuration
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.
Feature Name |
Releases |
Feature Information |
---|---|---|
BGP per Neighbor SoO Configuration |
Cisco IOS XE Release 2.1 |
The BGP per neighbor SOO configuration feature simplifies the configuration of the site-of-origin (SoO) parameter. The per neighbor SoO configuration introduces two new commands that can be configured in submodes under router configuration mode to set the SoO value. This feature was introduced on the Cisco ASR 1000 Series Aggregation Services Routers. The following commands were introduced by this feature: neighbor soo, soo. |