11-27-2020 11:53 AM
Hi ,
Is that possible to run multiple BGP instance in one router ? if not, why.? Please.
Ex:
Router BGP 500
Router BGP 600
Solved! Go to Solution.
11-27-2020 01:19 PM
Yes, BGP does multiple BGP instances like IPv4 and IPv6, VRFs and VPNs can run on the same router under same BGP AS number; those are called address families (address-family).
However, you can only run 1 BGP AS number on a router. you cannot enable BGP with different AS number if yo already running BGP.
Regards, ML
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11-27-2020 04:23 PM
Not like the way you have shown.
However, each router instance can run bgp with a different ASN.
You can also use local-as for changing your AS with a neighbor e.g. for migrating purposes.
HTH.
12-01-2020 04:52 AM
Thanks .
11-27-2020 01:19 PM
Yes, BGP does multiple BGP instances like IPv4 and IPv6, VRFs and VPNs can run on the same router under same BGP AS number; those are called address families (address-family).
However, you can only run 1 BGP AS number on a router. you cannot enable BGP with different AS number if yo already running BGP.
Regards, ML
**Please Rate All Helpful Responses **
11-27-2020 04:23 PM
Not like the way you have shown.
However, each router instance can run bgp with a different ASN.
You can also use local-as for changing your AS with a neighbor e.g. for migrating purposes.
HTH.
11-28-2020 12:16 AM
On a side note, I searched for any software that actually does support multiple BGP instances on the same router. QUAGGA does, just in case anybody is interested...
https://www.nongnu.org/quagga/docs/docs-multi/BGP-instance-and-view.html
11-28-2020 06:36 AM
why we need BGP instance in router ?
the BGP design is multi instance (as I think ) by default.
for example
I have one router with AS 100 it can connect to
AS 100 ibgp
AS 200 ebgp
AS 300 ebgp
AS 100 ibgp
do show ip BGP you will see all prefix from different AS even if you us only AS in your Router.
12-01-2020 04:52 AM
Thanks .
12-01-2020 05:23 AM
You are so so welcome
06-13-2022 12:29 PM
Was looking into this too. Need router to have completely separate routing tables for different vrf's. BGP on internet and we use BGP for different vendors and internal stuff that is not on the Internet. Was planning on a pair of routers that each handle Internet, WAN, and other routing. Would be surprising if even newer routers like Cat8500 can't have more than one totally independent BGP.
06-13-2022 12:37 PM
can you more elaborate? I think you misunderstand bgp instance.
06-13-2022 01:11 PM
Just want to have the router act like several virtual routers. VRF has been around for a long time. But, Cisco routers limit to only one BGP AS number for the whole router, from what I have read here. No really clear answers. If vrf contexts can have separate static routes, why can't they each have their own BGP routing as well, having zero to do with other vrf's? We can't have just one AS number because that is usually something given to us, not something we can make up.
I don't know precisely what you mean by a BGP "instance" and what you think I am misunderstanding.
thanks
06-13-2022 01:22 PM
Currently on ASR-1001-X:
toledo-router(config)#vrf definition hamburgers-vrf
toledo-router(config-vrf)#router bgp 60021
[error:] BGP is already running; AS is 64050
Want to do: (on newer router ??)
toledo-router(config)#vrf definition hamburgers-vrf
toledo-router(config-vrf)#router bgp 60021
address-family ipv4 ... etc
toledo-router(config)#vrf definition cheeseburgers-vrf
toledo-router(config-vrf)#router bgp 60022
address-family ipv4 ... etc
Cisco arbitrarily limits bgp to one AS. It is a decision on their part. What I am wondering is if the newer routers still do this or not.
thanks
06-13-2022 01:32 PM
BGP is already running; AS is 64050 <- this error appear in any cisco router config one BGP but under it you can local-as "different for each neighbor"
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13761-39.html
this link for this feature.
09-14-2022 11:59 PM
This is actually possible using ASR9000 routers.
As I remember 4 instance could ne used at the same time, but two instance is enough , for example, to move router from one MPLS domain to another...
The router supports maximum of 4 BGP instances.
Each BGP instance needs a unique router-id.
Only one Address Family can be configured under each BGP instance (VPNv4, VPNv6 and RT-Constrain can be configured under multiple BGP instances).
IPv4/IPv6 Unicast should be within the same BGP instance in which IPv4/IPv6 Labeled-Unicast is configured.
IPv4/IPv6 Multicast should be within the same BGP instance in which IPv4/IPv6 Unicast is configured.
All configuration changes for a single BGP instance can be committed together. However, configuration changes for multiple instances cannot be committed together.
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