Grouping of rib-out peers, Bgp4 restart – Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare Routing Configuration Guide
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BGP4 Restart
Grouping of RIB-out peers
To improve efficiency in the calculation of outbound route filters, the device groups BGP4 peers
together based on their outbound policies. To reduce RIB-out memory usage, the device then
groups the peers within an outbound policy group according to their RIB-out routes. All peers
sharing a single RIB-out route (up to 32 peers per group) also share a single physical RIB-out entry,
resulting in as much as a 30-fold memory usage reduction.
NOTE
RIB-out peer grouping is not shared between different VRFs or address families, and is not
supported for VPNV4 or L2VPN peers.
BGP4 Restart
The Restart feature supports high-availability routing. With this feature enabled, disruptions in
forwarding are minimized and route flapping is diminished to provide continuous service during the
time that a device is performing a restart.
Under normal operation, restarting a BGP4 device causes the network to be reconfigured. In this
situation, routes available through the restarting device are first deleted when the device goes
down, and are then rediscovered and added back to the routing tables when the device is back up
and running. In a network with devices that regularly restart, performance can degrade significantly
and limit availability of network resources. BGP4 restart dampens the network response and limits
route flapping by allowing routes to remain available between devices during a restart. BGP4
Restart operates between a device and peers, and must be configured on each participating
device.
A BGP4 device with Restart enabled advertises this capability to establish peering relationships
with other devices. After a restart begins, all of the routes from the restarting device are marked as
stale by neighbor devices, but continue to be used for the length of time configured for the restart
timer. After the device is restarted, it begins to receive routing updates from the peers. When the
restarting device receives the end-of-RIB marker that indicates it has received all of the BGP4 route
updates, all of the routes are recomputed and newly computed routes replace the routes labeled as
stale in the route map. If the device does not come back up within the time configured for the purge
timer, the routes marked stale are removed.
NOTE
A second management module must be installed for the device to function as a restart device. If the
device functions as a restart helper device only, there is no requirement for a secondary
management module.
The implementation of BGP4 Restart supports the following Internet Draft:
•
Draft-ietf-idr-restart-10.txt: restart mechanism for BGP4
For details concerning configuration of the BGP4 Restart feature, refer to