[j-nsp] Limit content of bgp.l3vpn.0

[Adam Vitkovsky]

Hey Saku,

> Saku Ytti [mailto:saku at ytti.fi]
> Sent: Thursday, September 29, 2016 12:30 PM
>
> On 29 September 2016 at 10:09, Adam Vitkovsky
> <Adam.Vitkovsky at gamma.co.uk> wrote:
> > Since Junos can't generate update msg based on commonalities in egress
> policies (i.e. "dynamic update peer-groups"), I believe it will put each
> neighbour in its own update-group and generate update message for each
> peer independently, even though multiple peers might request the same set
> of RTs (i.e. have same set of egress policies).
>
> I don't believe this is true.
>
> You can do show 'show bgp group | match Name' and you should see which
> neighbours are part of same update-group. You may have several update-
> groups with same Name but different index and different set of neighbours.
>

You got me thinking so I did a little test, details below.
Conclusion:
The automatic grouping based on commonalities in egress policies works only within a group but not between groups.
Also within a group, if peer is configured with unique export policies and thus moved to its own update group the peer is bounced.

So with regards to Johan's case, if he has all the peers in one group, then the "update-grouping" should actually work, although if it does, then peers might flap spontaneously as they are being moved from one group to the other (when PEs are configured with new RTs).
If he defined unique group for each peer, then update-grouping wasn't there in the first place so nothing to lose nothing to gain (possibly except the stability when export policies are changed).
So yeah worth testing in the lab first.

set protocols bgp group test type external
set protocols bgp group test family inet unicast
set protocols bgp group test export pe-loopbacks
set protocols bgp group test peer-as 64512
set protocols bgp group test neighbor 1.1.1.1

> show bgp group test
Group Type: External                               Local AS: 31655
  Name: test            Index: 1                   Flags: <>
  Export: [ pe-loopbacks ]
  Holdtime: 0
  Total peers: 1        Established: 1
  1.1.1.1
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10


set protocols bgp group test neighbor 2.2.2.2

> show bgp group test
Group Type: External                               Local AS: 31655
  Name: test            Index: 1                   Flags: <>
  Export: [ pe-loopbacks ]
  Holdtime: 0
  Total peers: 2        Established: 2
  1.1.1.1
  2.2.2.2
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10


set protocols bgp group test neighbor 2.2.2.2 export DEFAULT_ORIGINATE_EX
2.2.2.2 -will bounce
> show bgp group test
Group Type: External                               Local AS: 31655
  Name: test            Index: 1                   Flags: <>
  Export: [ pe-loopbacks ]
  Holdtime: 0
  Total peers: 1        Established: 1
  1.1.1.1
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10

Group Type: External                               Local AS: 31655
  Name: test            Index: 10                  Flags: <>
  Export: [ DEFAULT_ORIGINATE_EX ]
  Holdtime: 0
  Total peers: 1        Established: 0
  2.2.2.2
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10


set protocols bgp group test neighbor 1.1.1.1 export DEFAULT_ORIGINATE_EX
  1.1.1.1 -will bounce
> show bgp group test
Group Type: External                               Local AS: 31655
  Name: test            Index: 10                  Flags: <>
  Export: [ DEFAULT_ORIGINATE_EX ]
  Holdtime: 0
  Total peers: 2        Established: 1
  1.1.1.1
  2.2.2.2
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10


del protocols bgp group test neighbor 2.2.2.2
set protocols bgp group test2 type external
set protocols bgp group test2 family inet unicast
set protocols bgp group test2 export pe-loopbacks
set protocols bgp group test2 peer-as 64512
set protocols bgp group test2 neighbor 2.2.2.2 export DEFAULT_ORIGINATE_EX

show bgp group test
Group Type: External                               Local AS: 31655
  Name: test            Index: 10                  Flags: <>
  Export: [ DEFAULT_ORIGINATE_EX ]
  Holdtime: 0
  Total peers: 1        Established: 1
  1.1.1.1
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10

Group Type: External                               Local AS: 31655
  Name: test2           Index: 1                   Flags: <>
  Export: [ DEFAULT_ORIGINATE_EX ]
  Holdtime: 0
  Total peers: 1        Established: 0
  2.2.2.2
  Trace options:  all
  Trace file: /var/log/bgp-trace size 131072 files 10


adam





        Adam Vitkovsky
        IP Engineer

T:      0333 006 5936
E:      Adam.Vitkovsky at gamma.co.uk
W:      www.gamma.co.uk

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