Question about graceful restart timer
Hello bird users, one of our VIX customers (RS-Client) came up with a question about the graceful restart timer. At his Cisco he found: ------------ Graceful Restart Capability: advertised and received Remote Restart timer is 0 seconds ------------ We don't have anything related to graceful restart in our config, defaults should apply. At packet level, I found in BGP Open sent from bird: ------------ Capability: Route refresh capability Type: Route refresh capability (2) Length: 0 Capability: Graceful Restart capability Type: Graceful Restart capability (64) Length: 2 Restart Timers: 0x0000 0... .... .... .... = Restart: No .... 0000 0000 0000 = Time: 0 ------------ Next, I tried to set the timer explicitly, which ended up again with restart timer 0 in BGP Open. The only way to get the correct timer in the packet was to set graceful to yes in the protocol definition. ------ graceful restart time 10; graceful restart yes; ------ As far as I understand the default for graceful restart ("aware") should be enough to advertise capability and timer. I am grateful for every advice, regards Robert -- www.vix.at | www.aco.net robert.wein@univie.ac.at | RW2586-RIPE Vienna University Computer Center Tel: +43 1 4277-14046 | Fax: -14338
On Thu, Aug 25, 2016 at 08:23:09AM +0200, Robert Wein wrote:
Hello bird users,
one of our VIX customers (RS-Client) came up with a question about the graceful restart timer. At his Cisco he found:
------------ Graceful Restart Capability: advertised and received Remote Restart timer is 0 seconds ------------
We don't have anything related to graceful restart in our config, defaults should apply.
As far as I understand the default for graceful restart ("aware") should be enough to advertise capability and timer.
Restart timer specifies how long should peers wait for the BGP speaker to restart, therefore it makes sense only in full graceful restart mode. In receive-only mode ('aware') we always send zero. See RFC 4724: When a sender of this capability does not include any <AFI, SAFI> in the capability, it means that the sender is not capable of preserving its forwarding state during BGP restart, but supports procedures for the Receiving Speaker (as defined in Section 4.2 of this document). In that case, the value of the "Restart Time" field advertised by the sender is irrelevant. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
participants (2)
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Ondrej Zajicek -
Robert Wein