What is the signification of knwon, redistributing and advertised for Show ip route x.x.x.x (EIGRP route)

[Steph1963]

Hi to All,

I have noticed that when we are using EIGRP routing protocol, the show ip route is different from other protocol.

The show ip route provides the following information that does not to seem to be available with other routing protocols

  Known via
  Redistributing via
  Advertised by ospf 101

If we take the following network where EIGRP redistribute OSPF routes and OSPF redistribute EIGRP routes

We notice that the following information is available

R2#show ip route 3.3.3.3
Routing entry for 3.0.0.0/8
  Known via "eigrp 1", distance 90, metric 409600, type internal
  Redistributing via eigrp 1, ospf 101
  Advertised by ospf 101 subnets
  Last update from 10.0.0.2 on FastEthernet0/1, 00:05:02 ago
  Routing Descriptor Blocks:
  * 10.0.0.2, from 10.0.0.2, 00:05:02 ago, via FastEthernet0/1
      Route metric is 409600, traffic share count is 1
      Total delay is 6000 microseconds, minimum bandwidth is 10000 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 1/255, Hops 1

Question 1) Why does other routing protocols does not produce similar information

Question 2) What is the difference between a route redistributed and a route advertised

Thanks for your help
Stéphane

[vmiller]

In answer to your first question I would suggest that since Cisco developed EIGRP they could

pretty much determine all the details of what to display in messages. All the other IGPs (OSPF, RIP...)

are more standards driven.

As to the second question, a redistributed route is a route delivered from another routing process and placed in the local

process. That external process (for lack of a better word) could be static, connected BGP or another IGP. The determining factor

is that the redistributed route is not one that the local process would discover except by means of redistributon.

An advertised route is simply one that the local process is advertising as reachable in one way or another. It could be a redistributed route

from another AS.

[Steph1963]

Hi,

Thanks for your help

Would you include in your definition that redistributing a route can also include a route from the same process.

From the same example:

R3#show ip route 1.1.1.1

Routing entry for 1.1.1.1/32

Known via "eigrp 1", distance 170, metric 2560025856, type external

Redistributing via eigrp 1

The route seems to be known from eigrp 1 and also redistribute via eigrp 1. Base on the following and as per your saying

R2#show ip route 3.3.3.3

Routing entry for 3.0.0.0/8

Known via "eigrp 1", distance 90, metric 409600, type internal

Redistributing via eigrp 1, ospf 101

Advertised by ospf 101 subnets

Redistributing via eigrp 1, ospf 101 would means that the route is announced and eigrp 1 in ospf 101 while advertised by OSPF 101 subnets might indicate that the EIGRP route is redistributed by OSPF.

Thanks again for your help

Stephane

[vmiller]

In this case, i think that we have a semantics issue

your first example is an external route. note the distance value and the note the type.

the second one appears as an internal route to the eigrp process, and is being redistributed to ospf.

the use of the term redistributed via eigrp may be a bit muddy, distribute might be a better term in this case.

The trick is to check the admin distance that is the better indicator in eigrp of where the route came from.