External data Keywork on ROute

[Rupesh Kashyap]

Hi, What is the meaning of External Data ?

R>sh ip ei topology 10.4.6.0 255.255.255.0

IP-EIGRP (AS 1): Topology entry for 10.4.6.0/24

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 373760

Routing Descriptor Blocks:

10.3.1.2 (Multilink10), from 10.3.1.2, Send flag is 0x0

Composite metric is (373760/153600), Route is External

Vector metric:

Minimum bandwidth is 7936 Kbit

Total delay is 2000 microseconds

Reliability is 243/255

Load is 1/255

Minimum MTU is 1500

Hop count is 1

External data:

Originating router is 10.3.1.2

AS number of route is 65040

External protocol is BGP, external metric is 0

Administrator tag is 65140 (0x0000FE74)

[Giuseppe Larosa]

Hello Rupesh,

EIGRP external routes data structures contain additional fields:

the EIGRP router-id of the router that injected the route in the EIGRP domain.

10.3.1.2.

The protocol from which the route has been learned is BGP with BGP as number 65040.

the route tag is a copy of BGP AS number (this is a default).

The BGP metric MED is 0.

This information is carried to provide a way to rebuild (at least partially the AS path cannot be rebuilt) the original BGP route in another node.

Hope to help

Giuseppe