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Webcast-Catalyst9k
New Member

Regarding Protocol not going down

Hi friendz,

We have one point to point link of 10MBPS. when ever there is an outage with the ISP with the fiber outage,  line protocol of the physical interface is not going down. it will be up always, because of its state up,  traffic will not switch over to secondary. we have to manually make the primary interface shut to divert the trafiic.  we have terminated the lines to Fastethernet interfaces.

Could you kindly suggest what could be the problem.

Sh run on interface is as follows

interface FastEthernet1/0

description *** TATA Indicom  bandwidth 10000

ip address 10.96.252.38 255.255.255.252

duplex auto

speed auto

end

8 REPLIES
Gold

Regarding Protocol not going down

Its not unheard of in certain types of optical implementations.

For example, In the past we had Fast E terminations from the carrier on Cisco ONS devices. the fast e components were

actually switches. even with a ring cut, the switch side facing our hardware stayed up/up. Our only means at the time to detect a link outage was a neighbor loss log entry.Since we had redundant links, the clients never noticed.

What routing protocol are you using ?

New Member

Regarding Protocol not going down

Hi joseph, we are using, eigrp routing protocol

Hall of Fame Super Gold

Regarding Protocol not going down

It is interesting that you are using EIGRP as your dynamic routing protocol. As suggested by Joseph EIGRP is pretty good at detecting failure of the primary route and switching to a backup route. Is EIGRP running on this point to point link to the ISP?

HTH

Rick

Gold

Regarding Protocol not going down

To follow on to Mr. Burts comments:

In the environment we had, there were 2 EIGRP links, when one failed, the only syslog stuff we saw was a loss of neighbor.

With a little work, that was enough to let ops know that something was wrong on the metro link.

New Member

Regarding Protocol not going down

Hi Vmiller,

We are using EIGRP internally and BGP, static routes between our organization to ISP. so what could be the problem. when the neighbor is down, atleaset protocol has to go down, why its not happening?

Gold

Regarding Protocol not going down

how is the route to TATA defined to routing processes ?

As stated before, it is entirely possible for the physical link between your device and the next device to

stay UP, while the L3 protocol is down.

Assume for discussion a device that takes your ethernet handoff as ethernet, then maps that on to a sonet service (very common). If the Sonet service fails, there is no means to take the ethernet down between your device and the carriers

device.  that link status is independent of whatever is on the carrier side. The two link states are independent of each other.

I would consider looking at IP SLA for this.

Hall of Fame Super Gold

Regarding Protocol not going down

I agree with vmiller that we need more information. At first we were told that you use EIGRP. Then we are told that EIGRP is for internal and BGP, static routes to ISP. We could give you better answers if you provide more detail about the topology of the network and how things are configured.

Also vmiller makes a very good point that Ethernet interfaces frequently stay as line is up line protocol is up even when there is not layer 3 connectivity to the next hop. So if the route that you are asking about is a static route which goes out an Ethernet then his suggestion of using IP SLA is a very good suggestion and I agree with it.

So please give us some useful details about this route that is not working as you expect.

HTH

Rick

Super Bronze

Regarding Protocol not going down

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Posting

As Vmiller has noted, it's not unheard of on some physical topologies.  Dynamic routing protocols should note the logical disconnection but if you're doing static routing, I believe, depending on platform, you could use IP SLA to logically detect the link outage too.

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