On Mon, 21 Sep 1998, Barry L James wrote:
Hey all,
We just got a third T1, this time through UUNet and when I looked at their router configuration I got a little surprise. We ordered a point-to-point circuit that is being terminated at their detroit POP. The configuration, however, sets up the line as a frame relay encap on a sub-interface (on a Cisco, of course :). When I talked to my UUNet rep he advised that this was the way "every large ISP did it" which I knew wasn't exactly true since our MCI and AT&T (just recently transitioned from the BBN backbone to the AT&T network) does not use this configuration. He insisted that it was still a point to point and that the frame relay encapsulation was used to enhance the connection.
Well I don't know that this is the way every large ISP does it, but several do. That is at least how I did it with NetRail. You take all your T1 customers into CT3 cards on Cascade 9000s and then connect the 9000 to your routers.
Well, I had him grab an engineer (he was an SE) that could possibly explain it better to me (since the SE said F/R was used to decrease RIP broadcasts across their backbone) and the engineer said this (basically): the circuit is terminated in a cascade 9000 f/r switch (used for port density) which went to a HSSI interface in a Cisco 7xxx series router which connected directly to their ATM network. Therefore, the f/r encaps were needed to speak with the cascade. The engineer advised we had a full CIR and would not suffer any bandwidth loss from using f/r encap.
Correct.
Now, I guess my question is: am I getting sold the brooklyn bridge here?
Well no, but it does have some problems. A lot of the Cascades at UUNet are the old HSSI cards and have problems over 30 megs.
I mean, not that I wouldn't like to *own* the brooklyn bridge (well, I'd rather have the triboro or the washington, but anyway...). Is this f/r encap going have any adverse affect on the quality of this connection (assuming that this is *NOT* a point-to-point into a frame cloud) or am I getting shoveled a load of copralite?
Well you should be ok. Sure you MAY run into congestion issues, but you should be ok.
Thanks!
<> Nathan Stratton Telecom & ISP Consulting www.robotics.net nathan@robotics.net -- "No king is saved by the size of his army; no warrior escapes by his great strength." - Psalm 33:16
Barry
Barry L James | Mikrotec Internet Services, Inc (AS3801) Director R & D | 1001 Winchester Rd bjames@mis.net | Lexington KY 40505 http://www.mis.net/ | 606/266.5925 800/875.5095 Member AAAI, IEEE # 40277528 --- Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on. -- Winston Churchill