Users Guide

After the switch over, the graceful restart operation begins. Both routers reestablish their neighbor relationship and exchange their BGP
routes again. The helper continues to forward prefixes pointing to the restarting peer, and the restarting router continues to forward
traffic to its peers even though those neighbor relationships are restarting. When the restarting router receives all route updates from all
BGP peers that are graceful restart capable, the graceful restart is complete. BGP sessions become operational again.
Configure Border Gateway Protocol
BGP is disabled by default. To enable the BGP process and start to exchange information, assign an AS number and use commands in
ROUTER-BGP mode to configure a BGP neighbor.
BGP neighbor
adjacency changes
All BGP neighbor changes are logged
Fast external
fallover
Enabled
Graceful restart Disabled
Local preference 100
4-byte AS Enabled
MED 0
Route flap
dampening
parameters
• half-life = 15 minutes
• max-suppress-time = 60 minutes
• reuse = 750
• suppress = 2000
Timers
• keepalive = 60 seconds
• holdtime = 180 seconds
Add-path Disabled
Enable BGP
Before enabling BGP, assign a BGP router ID to the switch using the following command:
• In the ROUTER BGP mode, enter the router-id ip-address command. Where in, ip-address is the IP address
corresponding to a configured L3 interface (physical, loopback, or LAG).
BGP is disabled by default. The system supports one AS number — you must assign an AS number to your device. To establish BGP
sessions and route traffic, configure at least one BGP neighbor or peer. In BGP, routers with an established TCP connection are called
neighbors or peers. After a connection establishes, the neighbors exchange full BGP routing tables with incremental updates afterward.
Neighbors also exchange the KEEPALIVE messages to maintain the connection.
You can classify BGP neighbor routers or peers as internal or external. Connect EBGP peers directly, unless you enable EBGP multihop —
IBGP peers do not need direct connection. The IP address of an EBGP neighbor is usually the IP address of the interface directly
connected to the router. The BGP process first determines if all internal BGP peers are reachable, then it determines which peers outside
the AS are reachable.
1. Assign an AS number, and enter ROUTER-BGP mode from CONFIGURATION mode, from 1 to 65535 for 2-byte, 1 to 4294967295 for
4-byte. Only one AS number is supported per system. If you enter a 4-byte AS number, 4-byte AS support is enabled automatically.
router bgp as-number
2. Enter a neighbor in ROUTER-BGP mode.
neighbor ip-address
3. Add a remote AS in ROUTER-NEIGHBOR mode, from 1 to 65535 for 2-byte or 1 to 4294967295 for 4-byte.
remote-as as-number
Layer 3
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