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Independant opinions needed on our network.

Level 1
Level 1

Dear All,

Please see the attached diagram fron CNA.

Our sister site had a new building and the network it was supposed to resemble the network on this site with link redundancy as far as the edge switches.

After 6 months asking for the password to the equipment I finaly got it and started to plan the deployment of some phones, I got a little confused as to the layout of what had been done as CDP was not showing what I had expected.

I then used CNA to map out the site.

We have 1 main server room (at the top of the picture with the two 4507 cores and a number of fixed config 1U switches)

And 3 further wiring rooms at other points in the building with fixed config 1U switches.

(And a wan link to this site)

In my opinion the design as it stands is significantly flawed in redundacny with multiple points of failure, and its efficiency is very poor.

Comments Please.



7 Replies 7

Level 6
Level 6

If Icorrectly understood you picture,you have 2 links form each of departments to different switch in CO. I thinks is normal for redundancy


Posted by WebUser Aleksandr Yanovskiy

If it were me, and I had total control of what to put in I would do the following.

1) Set up an etherchannel with at least 2 links, have one etherchannel going to one dist switch, and another going to the other. That would you have 4 total physical links for redundancy, but 2 logical.

2) It looked like some of your switches were cascaded from other switches, I would make them have direct access to the dist switch using the same etherchannel setup as above.

3) I don't know how your routing is, but I would try to make sure there are reundant paths between dist and core as well asn between core and core.

1) That would be an improvement.

2) Your bang on, they have cascaded using 1Gb Copper. Personaly ( for the server room ) I would have just fired them straight back to the 4507 and not bother with the distro switch.

3) HSRP is configured.

One switch stack is showing ashaving no active link in CNA, although one of the vlans is up and it is working..


I'm personally not the biggest fan of CNA. I've seen devices that were working and up, not show up, and then pop up out of no where.

Yeah, CNA does some strange things. I just needed a way to visualise the layout for my line mangager in the easiest way in a short time.

My main concern is the resiliance of the design and the performance in some respect.

Our main site goe no more than 2 switches below the core.


Just to follow up on this a year later.......

The provider was told that the layout was substandard and needed changing. They said it was fine.

I e-mailed the diagram and asked them to describe the way in which it was

1) Highly Resiliant

2) Designed for Performance

3) Matched closely our sister site

They admitted it was dreadful and planned the reworking to an accepted level.


Hello Robin,

you have been very kind in providing a feedback on this issue giving an happy end to the story.

Best Regards


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