Problem Statement:
=================
In scale setup BGP sessions start flapping.
RCA:
====
In virtualized environment there are multiple places where
MTU need to be set. If there are some places were MTU is not set
properly then there is chances that BGP packets get fragmented,
in scale setup this will lead to BGP session flap.
Fix:
====
A new tcp option is provided as part of this implementation,
which can be configured per neighbor and helps to set the TCP
max segment size. User need to derive the path MTU between the BGP
neighbors and set that value as part of tcp-mss setting.
1. CLI Configuration:
[no] neighbor <A.B.C.D|X:X::X:X|WORD> tcp-mss (1-65535)
2. Running config
frr# show running-config
router bgp 100
neighbor 198.51.100.2 tcp-mss 150 => new entry
neighbor 2001:DB8::2 tcp-mss 400 => new entry
3. Show command
frr# show bgp neighbors 198.51.100.2
BGP neighbor is 198.51.100.2, remote AS 100, local AS 100, internal link
Hostname: frr
Configured tcp-mss is 150, synced tcp-mss is 138 => new display
4. Show command json output
frr# show bgp neighbors 2001:DB8::2 json
{
"2001:DB8::2":{
"remoteAs":100,
"bgpTimerKeepAliveIntervalMsecs":60000,
"bgpTcpMssConfigured":400, => new entry
"bgpTcpMssSynced":388, => new entry
Risk:
=====
Low - This is a config driven feature and it sets the max segment
size for the TCP session between BGP peers.
Tests Executed:
===============
Have done manual testing with three router topology.
1. Executed basic config and un config scenarios
2. Verified if the config is updated in running config
during config and no config operation
3. Verified the show command output in both CLI format and
JSON format.
4. Verified if TCP SYN messages carry the max segment size
in their initial packets.
5. Verified the behaviour during clear bgp session.
6. done packet capture to see if the new segment size
takes effect.
Signed-off-by: Abhinay Ramesh <rabhinay@vmware.com>
Also
- update info about new packages needed as libcares.
- create proper links to libyang so ld can find the lib.
Signed-off-by: Javier Garcia <javier.garcia@voltanet.io>
Currently we have a "route-map optimization" command which is entered
from inside the route-map entry but actually applies to the whole
route-map. In addition, this command is not shown in the running-config
and not stored to the startup-config during "write".
Let's add a new command on the config node level to control this setting
and show it in the running-config to make possible to save it during
"write".
The old command is saved for the backward compatibility but hidden and
marked as deprecated.
Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
Most of these are many, many years out of date. All of them vary
randomly in quality. They show up by default in packages where they
aren't really useful now that we use integrated config. Remove them.
The useful ones have been moved to the docs.
Signed-off-by: Quentin Young <qlyoung@nvidia.com>
Update workflow.rst to state that commit messages consisting solely of
program output, or that otherwise fail to adequately summarize the
changes being made, are unacceptable.
Signed-off-by: Quentin Young <qlyoung@nvidia.com>
