Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH 사용자 설명서

When entering an AS number in a policy file, you must enter a 

unique 2-byte or 4-byte AS number. The transition AS number, AS 
23456, is not supported in policy files.

To delete a static BGP network, use the following command:

configure bgp delete network {address-family [ipv4-unicast | ipv4-multicast]} 

[all | <ipaddress/mask length>]

 

Graceful BGP Restart

It is possible for BGP control functions to restart without disrupting traffic forwarding. Without 
graceful restart, adjacent routers will assume that information previously received from the 
restarting router is stale and won’t be used to forward traffic to that router. However, in many 
cases, two conditions exist that allow the router restarting BGP to continue to forward traffic 
correctly. The first condition is that forwarding can continue while the control function is 
restarted. Most modern router system designs separate the forwarding function from the 
control function so that traffic can still be forwarded independent of the state of the BGP 
function. Routes learned through BGP remain in the routing table and packets continue to be 
forwarded. The second condition required for graceful restart is that the network remain 
stable during the restart period. If the network topology is not changing, the current routing 
table remains correct. Often, networks can remain stable during the time for restarting BGP.

With graceful BGP restart, routes received from a restarting router are marked as stale, but 
traffic continues to be forwarded over these routes during the restart process.

Routers involved with graceful restart fill one of two roles: the restarting router or the 
receiving router. When a receiving router detects that the TCP connection with its peer is 
reset, it assumes that the peer has entered graceful restart. If the neighboring routers are 
configured to help with the graceful restart (receiver-mode), they will continue to advertise the 
restarting router as if it was fully functional. Traffic continues to be routed as though the 
restarting router is fully functional. The receiver router will continue in receiver mode until the 
restarting router re-establishes the TCP session, indicating successful termination of graceful 
restart, the restart timers expire. A router can be configured for graceful restart, and for 
receiver-mode separately. A router can be a receiver when its neighbor restarts, and can in 
turn be helped by a neighbor receiver-mode router if it restarts.

Two types of graceful restarts are defined: planned and unplanned. A planned restart occurs 
when the software module for BGP is upgraded, or if the router operator decides to restart 
the BGP control function for some reason. An unplanned restart occurs when there is some 
kind of system failure that causes a remote reboot or a crash of BGP, or when an MSM/MM 
failover occurs. You can decide to configure a router to enter graceful restart for only planned