AS-OVERRIDE VS ALLOWAS-IN
Below table describes the difference between AS-OVERRIDE and ALLOWAS-IN;
PARAMETER | AS-OVERRIDE | ALLOWAS-IN |
Overview | Used by PE to modify the AS Path so that prefix is not dropped based on BGP default behaviour to disallow its own AS number in the AS Path of prefix. | Used as an exception AS path loop prevention mechanism where BGP default behaviour is to disallow its own AS number in the AS Path of prefix. |
Output | Replaces AS in BGP updates to local AS | Permits BGP updates containing local AS |
Configured at | Servicer provider end (on PE) | Customer end (on CE) |
Configuration | Configured under router bgp <AS No> <address-family ipv4 vrf “name”> neighbor <IP> as-override | Configured under router bgp <AS No> neighbor <IP> allowas-in
|
Scope | Configuration performed at the Service provider end | Configuration performed at Customer premises end. |
AS Path | AS Path information is modified | AS Path Information is not modified |
SOURCE:https://ipwithease.com
Tag:comparison