Do BGP hold timers have to match?

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Do BGP hold timers have to match?

This message also carries hold time configured on the peer. The common myth is both BGP peer mush have matching hold time and keep alive timer for BGP neighbor relationship. It is not true! Another myth is BGP peer sends keep alive timer in open message, it is not true either!

How do I set BGP timer?

To adjust BGP network timers, use the timers bgp router configuration command. To reset the BGP timing defaults, use the no form of this command. Frequency (in seconds) with which the Cisco IOS software sends keepalive messages to its peer. The default is 60 sec.

How do I test BGP timer?

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To verify currently configured advertisement timer, you can look on show ip bgp neighbors to see it. The same output for iBGP session would show you advertisement timer set to 0 second by default as inside one AS, the updates should be propagated immediately.

Are BGP timers negotiated?

BGP KEEPALIVE and HOLD-DOWN Once the peering between two peers is UP, router starts a hold-down timer counting from 0 second up. NOTE: New keepalives will take effect only after new BGP session establishment as they are transferred and negotiated to the lower values from the two peers in the OPEN messages.

What is BGP convergence time?

Convergence time is an important metric for routing protocols, such as the BGP. Convergence time is the period required by the BGP to reroute the pacNet after a routing change. Significant research on BGP convergence time using Internet measurements has revealed the problematic slowness BGP convergence [3].

Why is BGP slow?

Failure detection and propagation by means of BGP mechanics is slow, and depends on the number of affected prefixes. Therefore, the more severe is the damage, the slower it is propagated. Some other, non-BGP mechanism needs to be used to report network failures and trigger BGP re-convergence.

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How old is BGP?

The Border Gateway Protocol was first described in 1989 in RFC 1105, and has been in use on the Internet since 1994. IPv6 BGP was first defined in RFC 1654 in 1994, and it was improved to RFC 2283 in 1998.

What is the hold time for BGP sessions?

When establishing a BGP session, the routers use the smaller Hold Time value contained in the two router’s OPEN messages. The Hold Time value must be at least three seconds, or zero. For Cisco routers the default hold timer is 180 seconds.

What are basic BGP times and how are they calculated?

First basic BGP times are Keepalive and Hold-down timer intervals. By default, keepalive timer is 60 seconds and hold-down timer is 3xkeepalive or 180seconds. Once the peering between two peers is UP, router starts a hold-down timer counting from 0 second up.

How often are keepalive messages exchanged between BGP neighbors?

Keepalive messages are exchanged every one-third of the Hold Timer agreed upon between the two BGP routers. Cisco devices have a default Hold Time of 180 seconds, so the default Keepalive interval is 60 seconds. If the Hold Time is set for zero, no Keepalive messages are sent between the BGP neighbors.

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What is the default keepalive interval for BGP 3 15?

The timers bgp 3 15 command makes the router send keepalives every three seconds and use a hold timer of 15 seconds by default. For the session to neighbor 192.0.2.31 a keepalive interval of ten seconds is used, and a hold time of 32 seconds.