Description

When configuring over 16 unique local-as the following error is reported: Maximum number of local-ases exceeded.

Symptoms

labroot@Fall# show | match local-as | display set
set routing-instances VRF-1 protocols bgp group primary local-as 1
set routing-instances VRF-10 protocols bgp group primary local-as 10
set routing-instances VRF-11 protocols bgp group primary local-as 11
set routing-instances VRF-12 protocols bgp group primary local-as 12
set routing-instances VRF-13 protocols bgp group primary local-as 13
set routing-instances VRF-14 protocols bgp group primary local-as 14
set routing-instances VRF-15 protocols bgp group primary local-as 15
set routing-instances VRF-17 protocols bgp group primary local-as 17
set routing-instances VRF-18 protocols bgp group primary local-as 18
set routing-instances VRF-19 protocols bgp group primary local-as 19
set routing-instances VRF-2 protocols bgp group primary local-as 2
set routing-instances VRF-20 protocols bgp group primary local-as 20
set routing-instances VRF-21 protocols bgp group primary local-as 21
set routing-instances VRF-22 protocols bgp group primary local-as 22
set routing-instances VRF-3 protocols bgp group primary local-as 3
set routing-instances VRF-4 protocols bgp group primary local-as 4
set routing-instances VRF-5 protocols bgp group primary local-as 5
set routing-instances VRF-6 protocols bgp group primary local-as 6
set routing-instances VRF-7 protocols bgp group primary local-as 7
set routing-instances VRF-8 protocols bgp group primary local-as 8
set routing-instances VRF-9 protocols bgp group primary local-as 9

Adding a 17th local-as gives the following commit error:

labroot@Fall# set routing-instances VRF-17 protocols bgp group primary local-as 17

labroot@Fall# commit check
[edit routing-instances VRF-17 protocols bgp group primary]
  'local-as'
    Maximum number of local-ases exceeded
error: configuration check-out failed

Solution

This is system limitation of 16 unique local ASes.

There are other options like as-override, remove-private, or loops. One other workaround is to use use independent AS Domains.

Here is an error on the 17th instance committed without independent AS Domains:

labroot@Fall# commit check
[edit routing-instances VRF-17 protocols bgp group primary]
  'local-as'
    Maximum number of local-ases exceeded
error: configuration check-out failed

Workaround: After configuring each routing instance with independent AS Domains, we have 22 routing-instances with a unique AS number in each:

labroot@Fall# set routing-instances VRF-1 routing-options autonomous-system 1
labroot@Fall# set routing-instances VRF-1 routing-options autonomous-system independent-domain no-attrset
labroot@Fall# commit check
re0:
configuration check succeeds
 

Modification History

2022-10-31: Added the commit check passed, last line, to point out commit is passing after change 

2025-06-23: Added the information details.

2025-06-27: Added the information details.

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