Cisco Cisco Packet Data Gateway (PDG)
Routing
BGP-4 Routing ▀
ASR 5500 System Administration Guide, StarOS Release 17 ▄
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ICSR and SRP Groups
BGP is employed with Interchassis Session Recovery (ICSR) configurations linked via Service Redundancy Protocol
(SRP). By default an ICSR failover is triggered when all BGP peers within a context are down.
(SRP). By default an ICSR failover is triggered when all BGP peers within a context are down.
Optionally, you can configure SRP peer groups within a context. ICSR failover would then occur if all peers within a
group fail. This option is useful in deployments in which a combination of IPv4 and IPv6 peers are spread across
multiple paired VLANs, and IPv4 or IPv6 connectivity is lost by all members of a peer group.
group fail. This option is useful in deployments in which a combination of IPv4 and IPv6 peers are spread across
multiple paired VLANs, and IPv4 or IPv6 connectivity is lost by all members of a peer group.
For additional information refer to Interchassis Session Recovery in this guide and the description of the monitor bgp,
monitor diameter and monitor authentication-probe commands in the Service Redundancy Protocol Configuration
Mode Commands chapter of the Command Line Interface Reference.
monitor diameter and monitor authentication-probe commands in the Service Redundancy Protocol Configuration
Mode Commands chapter of the Command Line Interface Reference.
Advertising BGP Routes from a Standby ICSR Chassis
An SRP Configuration mode command enables advertising BGP routes from an ICSR chassis in standby state. This
command and its keywords allow an operator to take advantage of faster network convergence accrued from deploying
BGP Prefix Independent Convergence (PIC) in the Optical Transport Network Generation Next (OTNGN).
command and its keywords allow an operator to take advantage of faster network convergence accrued from deploying
BGP Prefix Independent Convergence (PIC) in the Optical Transport Network Generation Next (OTNGN).
BGP PIC is intended to improve network convergence which will safely allow for setting aggressive ICSR failure
detection timers.
detection timers.
configure
context context_name
service-redundancy-protocol
advertise-routes-in-standby-state [ hold-off-time hold-off-time ] [
reset-bfd-nbrs bfd-down-time ]
reset-bfd-nbrs bfd-down-time ]
end
Notes:
hold-off-time hold-off-time delays advertising the BGP routes until the timer expires. Specify hold-off-time in
seconds as an integer from 1 to 300.
After resetting BFD, reset-bfd-nbrs bfd-down-time keeps the BFD sessions down for the configured number of
milliseconds to improve network convergence. Specify bfd-down-time as an integer from 50 to 120000.
Configurable BGP Route Advertisement Interval for ICSR
By default, the MinRtAdvInterval is set for each peer with a value of 5 seconds for an iBGP peer and 30 seconds for an
eBGP peer. An operator can use the neighbor identifier advertisement-interval command to globally change the
default interval.
eBGP peer. An operator can use the neighbor identifier advertisement-interval command to globally change the
default interval.
The BGP advertisement-interval can also be separately set for each address family. If configured, this value over-rides
the peer's default advertisement-interval for that address-family only. BGP will send route update-message for each
AFI/SAFI based on the advertisement-interval configured for that AFI/SAFI. If no AFI/SAFI advertisement-interval is
configured, the peer-based default advertisement-interval is used.
the peer's default advertisement-interval for that address-family only. BGP will send route update-message for each
AFI/SAFI based on the advertisement-interval configured for that AFI/SAFI. If no AFI/SAFI advertisement-interval is
configured, the peer-based default advertisement-interval is used.
In ICSR configurations, this feature can be used to speed route advertisements and improve network convergence times.