ATM WAN expansion

[tllevans]

My WAN core consists of several 7206 routers with DS3 ATM interfaces (PA-A2-4T1C-T3ATM) connecting to a central-site LS1010 and 7206 combination via OC3 ATM ports. Each site has a 10Mbps VBR NRT VCC for data and 4 1.787Mbps CBR CES T1's for voice trunking to the central site. Each site also connects to as many as 8 smaller sites via standard T1's terminating in the 7206's 8-port T1/CSU PA . I need to expand the ATM network to '2nd level' (medium sized) sites, but the voice trunking via CBR CES T1's will go to primary sites that are already maxed out on CES ports--the 7206 can only handle 4 CES T1's. I need either more ATM CES T1 port capacity in the 7206's or a way to terminate non-ATM T1's in an 8510MSR port adapter like the PA-MC-8T1 I used in the 7206. I know I could solve this by adding a 3640 or something to bring in the non-ATM T1's, but I'm looking for a 'cleaner' alternative. VOIP is not an option.

[lldygowski]

I would like to help you, but need some clarifications. Are the existing sites the primary sites and are these the big sites when compared to medium sized sites you mention? Will the medium have to go through the primary sites to get to the central sites?

Why is VoIP for trunking not an option? There are good solutions for this on 7206s.

CES is OK for limited T1s, but it gets expensive once you get past a certain number of ports . Are these private line DS3s or are you using a public ATM service from a carrier? Are you running CCS or CAS on the T1s?

Sounds like you need ATM switching capability in the primary sites to allow for more CES ports. The 1010s or equivalent can do this, but I may not understand the problem as you see it. Do you have 8510s? Please elaborate.

[tllevans]

Voice trunks from the 7 'large' sites go to the central site. The 12 'medium' sites I need to add to the ATM fabric use 'clear-channel T1's' to connect 'their EPN's (extended PBX carriers) to Lucent G3R PBX's at the large sites. Their 10Mbps data pipes will go to the central site.

We're not about to scrap some $30 million in PBX hardware and phones, and spend that much or more for new hardware, to convert to VOIP and IP phones. The current VOIP trunking hardware at around $20K per T1 is likewise cost prohibitive considering the number of trunks and voice T1's we need to handle.

We're using a public ATM service from a carrier. It is far more cost efficient than leased point-to-point DS3's or 'dark fiber' since there's no 'distance' factor in the billing. CBR CES T1's within an existing ATM netowrk ar far less costly (around $50 per 1Mbps) than point-to-point T1's ($250-$750 each). VOIP would drive us to larger VBR/NRT pipes anyhow (at $33 per Mbps) so the cost would be a wash.

I intend to replace existing 7206's at those G3R PBX sites that need more CES capacity with 8510's. Those 7206's can be re-deployed to the new 'medium' sites that don't need more than 2 or 3 ports for CES T1's.

The only thing the 7206 does for me that the 8510 can't is terminate point-to-point T1's coming from routers at 'small' sites. Conversely, the only thing missing from the 7206 is a 4-port CES PA

[jwitherell]

I have a customer who has 5 LS1010s each with a 4-port OC-3 PAM and multiple T1 CES PAMs. We tried to use them for T1 multiplexing over single mode fiber on their campus Nortel SL-1 PBX. We spent a year trying to get it working, and never did. The reason was that the SL-1 PB uses a proprietary altered T1 signal that required the LS1010 to use an unframed, unstructured mode, which the LS1010 doesn't do.

If you see where you would use more LS1010s, I know the customer would be happy to sell them to you dirt cheap, just to recover part of the costs. They were bought new from Cisco in 2000, and were in computer room environment for a year before being pulled out.

The only reason I mention this is because you mentioned that your LS1010 seems to have the same PAMs that the customer has. If this seems appealling, let me know. I could ask out Cisco sales rep if they would make a concession on relicensing or maintenance certification, which they may do for us.