- 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
- 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 Link Bandwidth
- 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)
- 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
BGP Graceful Shutdown
The BGP Graceful Shutdown feature reduces or eliminates the loss of traffic along a link being shut down for maintenance. Routers always have a valid route available during the convergence process. This feature is used primarily for maintenance on a link between a Provider Edge (PE), PE-PE, PE- Route Reflector (RR), PE-Customer Edge (CE) and CE.
- Finding Feature Information
- Information About BGP Graceful Shutdown
- How to Configure BGP Graceful Shutdown
- Configuration Examples for BGP Graceful Shutdown
- Additional References
- Feature Information for BGP Graceful Shutdown
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.
Information About BGP Graceful Shutdown
Purpose and Benefits of BGP Graceful Shutdown
There are times when planned maintenance operations cause routing changes in BGP. After the shutdown of eBGP and iBGP peering sessions between autonomous system border routers (ASBRs), BGP devices are temporarily unreachable during BGP convergence. The goal of gracefully shutting down one or more BGP sessions is to minimize traffic loss during the planned shutdown and subsequent reestablishment of the sessions.
The BGP Graceful Shutdown feature reduces or eliminates the loss of inbound or outbound traffic flows that were initially forwarded along the peering link that is being shut down for maintenance. This feature is primarily for PE-CE, PE-RR and PE-PE links. Lowering the local preference for paths received over the session being shutdown renders the affected paths less preferred by the BGP decision process, but still allows the paths to be used during the convergence while alternative paths are propagated to the affected devices. Therefore, devices always have a valid route available during the convergence process.
The feature also allows vendors to provide a graceful shutdown mechanism that does not require any router reconfiguration at maintenance time. The benefits of the BGP Graceful Shutdown feature are fewer lost packets and less time spent reconfiguring devices.
GSHUT Community
The GSHUT community is a well-known community used in conjunction with the BGP Graceful Shutdown feature. The GSHUT community attribute is applied to a neighbor specified by the neighbor shutdown graceful command, thereby gracefully shutting down the link in an expected number of seconds. The GSHUT community is always sent by the GSHUT initiator.
The GSHUT community is specified in a community list, which is referenced by a route map and then used to make policy routing decisions.
The GSHUT community can also be used in the show ip bgp community command to limit output to GSHUT routes.
BGP GSHUT Enhancement
The BGP Graceful Shutdown (GSHUT) Enhancement feature enables graceful shutdown of either all neighbors or only virtual routing and forwarding (VRF) neighbors across BGP sessions. To enable the BGP GSHUT enhancement feature on the device, you must configure either the community keyword or the local-preference keyword in the bgp graceful-shutdown all command. Use the activate keyword to activate graceful shutdown either across all neighbors or only across all VRF neighbors, across all BGP sessions.
How to Configure BGP Graceful Shutdown
Shutting Down a BGP Link Gracefully
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
neighbor
{ipv4-address
|
ipv6-address}
remote-as
number
5.
neighbor
{ipv4-address |
ipv6-address |
peer-group-name}
shutdown
graceful
seconds {community
value [local-preference
value] |
local-preference
value}
6.
end
7.
show
ip
bgp
community
gshut
DETAILED STEPS
Filtering BGP Routes Based on the GSHUT Community
Perform this task on a BGP peer to the device where you enabled the BGP Graceful Shutdown feature.
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
neighbor
{ipv4-address |
ipv6-address}
remote-as
number
5.
neighbor
{ipv4-address |
ipv6-address}
activate
6.
neighbor
{ipv4-address |
ipv6-address}
send-community
7.
exit
8.
route-map
map-tag
[permit |
deny] [sequence-number]
9.
match community
{standard-list-number |
expanded-list-number |
community-list-name [exact]}
10.
exit
11.
ip community-list
{standard |
standard
list-name} {deny |
permit}
gshut
12.
router
bgp
autonomous-system-number
13.
neighbor
address
route-map
map-name
in
DETAILED STEPS
Configuring BGP GSHUT Enhancement
1.
enable
2.
configure
terminal
3.
router
bgp
autonomous-system-number
4.
bgp graceful-shutdown
all {neighbors
|
vrfs}
shutdown-time {community
community-value [local-preference
local-pref-value]
|
local-preference
local-pref-value [community
community-value]}
5.
bgp graceful-shutdown
all {neighbors
|
vrfs}
activate
6.
end
7.
show ip bgp
8.
show
running-config
DETAILED STEPS
Configuration Examples for BGP Graceful Shutdown
Example: Shutting Down a BGP Link Gracefully
Graceful Shutdown While Setting a Local-Preference
This example gracefully shuts down the link to the specified neighbor in 600 seconds, adds the GSHUT community to the route, and sets a local preference of 500 for the route.
router bgp 1000 neighbor 2001:db8:5::1 remote-as 2000 neighbor 2001:db8:5::1 shutdown graceful 600 local-preference 500 neighbor 2001:db8:5::1 send-community exit
Graceful Shutdown While Setting an Additional Community
This example gracefully shuts down the link to the specified neighbor in 600 seconds, and adds the GSHUT community and numbered community to the route.
router bgp 1000 neighbor 2001:db8:5::1 remote-as 2000 neighbor 2001:db8:5::1 shutdown graceful 600 community 1400 neighbor 2001:db8:5::1 send-community exit
Graceful Shutdown while Setting an Additional Community and Local-Preference
This example gracefully shuts down the link to the specified neighbor in 600 seconds, adds the GSHUT community and the numbered community to the route, and sets a local preference of 500 to the route.
router bgp 1000 neighbor 2001:db8:5::1 remote-as 2000 neighbor 2001:db8:5::1 shutdown graceful 600 community 1400 local-preference 500 neighbor 2001:db8:5::1 send-community exit
Example: Filtering BGP Routes Based on the GSHUT Community
In additional to being able to gracefully shut down a BGP route, another use of the GSHUT community is to configure a community list to filter routes with this community from getting into the BGP routing table.
This example illustrates how to use a community list to filter incoming BGP routes based on the GSHUT community. In this example, a route map named RM_GSHUT denies routes based on a standard community list named GSHUT. The community list contains routes with the GSHUT community. The route map is then applied to incoming routes from the neighbor at 2001:db8:4::1.
router bgp 2000 neighbor 2001:db8:4::1 remote-as 1000 neighbor 2001:db8:4::1 activate neighbor 2001:db8:4::1 send-community exit route-map RM_GSHUT deny 10 match community GSHUT exit ip community-list standard GSHUT permit gshut router bgp 2000 neighbor 2001:db8:4::1 route-map RM_GSHUT in
Example: BGP GSHUT Enhancement
The following example shows how to enable and activate the BGP GSHUT enhancement feature across all neighbors. In this example, the neighbors are configured to gracefully shutdown within the specified duration of 180 seconds.
Device> enable Device# configure terminal Device(config)# router bgp 65000 Device(config-router)# bgp graceful-shutdown all neighbors 180 local-preference 20 community 10 Device(config-router)# bgp graceful-shutdown all neighbors activate Device(config-router)# end
Following is sample output from the show ip bgp command, which displays the graceful shutdown time for each neighbor. In this example, there are two IPv4 neighbors configured with IP address 10.2.2.2 and 172.16.2.1 and one VRF neighbor, tagged v1, is configured with IP address 192.168.1.1.
Device# show ip bgp neighbors 10.2.2.2 | include shutdown Graceful Shutdown Timer running, schedule to reset the peer in 00:02:47 seconds Graceful Shutdown Localpref set to 20 Graceful Shutdown Community set to 10 Device# show ip bgp neighbors 172.16.2.1 | include shutdown Graceful Shutdown Timer running, schedule to reset the peer in 00:02:38 seconds Graceful Shutdown Localpref set to 20 Graceful Shutdown Community set to 10 Device# show ip bgp vpnv4 vrf v1 neighbors 192.168.1.1 | include shutdown Graceful Shutdown Timer running, schedule to reset the peer in 00:01:45 seconds Graceful Shutdown Localpref set to 20 Graceful Shutdown Community set to 10
Following is sample output from the show running-config command, which displays information associated with the BGP session in router configuration mode:
Device# show running-config | session router bgp router bgp 65000 bgp log-neighbor-changes bgp graceful-shutdown all neighbors 180 local-preference 20 community 10 network 10.1.1.0 mask 255.255.255.0 neighbor 10.2.2.2 remote-as 40 neighbor 10.2.2.2 shutdown neighbor 172.16.2.1 remote-as 10 neighbor 172.16.2.1 shutdown ! address-family vpnv4 neighbor 172.16.2.1 activate neighbor 172.16.2.1 send-community both exit-address-family ! address-family ipv4 vrf v1 neighbor 192.168.1.1 remote-as 30 neighbor 192.168.1.1 shutdown neighbor 192.168.1.1 activate neighbor 192.168.1.1 send-community both exit-address-family
Additional References
Related Documents
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
BGP commands |
Standards and RFCs
Standard/RFC |
Title |
---|---|
RFC 6198 |
Requirements for the Graceful Shutdown of BGP Sessions |
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 Graceful Shutdown
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 Graceful Shutdown |
Cisco IOS XE Release 3.6S Cisco IOS XE Release 3.7S |
The BGP Graceful Shutdown feature reduces or eliminates the loss of traffic along a link being shut down for maintenance. Routers always have a valid route available during the convergence process. In Cisco IOS XE Release 3.7S, support was added for the Cisco ASR 903 router. The following commands were modified: ip community-list, neighbor shutdown, show ip bgp community, and show ip bgp vpnv4. |
BGP GSHUT Enhancement |
Cisco IOS XE Release 3.11S |
The BGP Graceful Shutdown (GSHUT) Enhancement feature enables graceful shutdown of either all neighbors or only virtual routing and forwarding (VRF) neighbors across BGP sessions. The following command was introduced: bgp graceful-shutdown all. |