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Community Member

Problem in Back to back connection of HSSI Port Adapter

We have two 75xx routers and recently connected these two router through HSSI Port adapters via NULL HSSI Cable. We have done following config on routers.

a. Router 1, with 12.1 IOS

interface Hssi3/0/0

ip address

ip route-cache distributed

hssi dce

clockrate 51840000

no cdp enable

b. Router 2 : IOS 12.0(18ST)

interface hssi 3/0/0

ip address

ip route-cache distributed

hssi internal-clock

no cdp enable

We are expereinceing a very odd behaviour on the HSSI Port of Router 1, where the input rate of this port adapter is approx. double of the output-rate of HSSI Port Adapter of Router 2.

Request for yr quick advise on this ODD behaviour.

Community Member

Re: Problem in Back to back connection of HSSI Port Adapter

I have used the HSSI interfaces extensively in recent years. I was a little confused by your config (I have never set up a back-to-back scenario) so I looked it up on CCO. Sure enough, it is exactly as you have it. However, this note did catch my eye:

This configuration was developed and tested for use with Cisco IOS® Software Releases 12.1(6),12.1(6)T or later

I noticed that Router 2 is 12.0. Also, I am not sure I understand you problem exactly. What do you mean by the input rate is approx. double the output? Do you mean packets when looking at the interface output statistics?

Community Member

Re: Problem in Back to back connection of HSSI Port Adapter

Dear Scott

Thanks for response.

1.This back to back config has been done to connect our router to BT router at London to make connectivity to Internet.

2. The config is as per Cisco Document""

3. Yes I am ref. the difference between 5 min output-rate of BT router i.e. Router 2 and Input Rate of our Router i.e. Router 1. The Router 1 does has IOS 12.1(6) and as per given document router 2 may still have ios 12.0.

4. As per my recent TAC case discussion with Cisco, I have removed the config(hssi dce anc clockrate command) from router 1 and excuted command "hssi internal clock" but said problem persists.

It would great help to have some valuable inputs froom all of you to resolve this issue.



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