[c-nsp] Best ATM switch, BPX woes

[Clayton Zekelman]

You can try shaping your PVC's before they hit the BPX. I typically run no shaping/policing in my core, and make sure all my edge devices do it first - compliance to traffic policies on the edge, no brains in the middle.

The 6400 UAC without NRP cards makes a decent ATM switch.  They're somewhat akin to a LS1010 from a configuration point of view, and since they're EOL, they're cheap.

Electrical interfaces are on the back, optical on the front - you can create PVC's between any interface, front or back.

I have a few in my network.  OC3MM interfaces are rare, so be prepared to use OC3SMI.

I never did figure out why people hate ATM so much.  We've been using it in our core for years, and its rock solid reliable.

----- Original Message ---------------

Subject: [c-nsp] Best ATM switch, BPX woes
   From: Chris Cappuccio <chris at nmedia.net>
   Date: Fri, 3 Dec 2004 00:10:31 -0800
     To: cisco-nsp at puck.nether.net

>Everyone hates ATM, so there are all these cheap switches out there.  Really
>cheap.  And I happen to need one....
>
>I want to talk DS3 and OC3 to:
>
>1. Cisco 7xxx series (PA-A3)
>2. Public ATM network
>3. Various ATM DSLAMs
>4. Other ISPs who buy DSL services from us and the public ATM network
>5. maybe VoATM DLCs
>6. maybe VoATM port on a Softswitch
>7. and maybe OC3 or OC12 to 6400UAC in the future
>
>So, we'll have heavy traffic patterns that eat up card buffers!
>
>Of course, the point of the switch is to allow us to distribute the DSLAMs
>and public ATM network to our routers and other ISP routers, and possibly
>consolidate remote DSLAM links and DLC links on the same trunks.  (Or maybe
>we will use VoIP DLCs, but I'd rather have something that can reliably emulate
>TDM down to the voice channel... I'd rather not be known as the provider that
>you can't make a modem call with)
>
>Today, I am using some old StrataCom BPX-15 boxes, which are the same
>as the early Cisco BPX 8600's with the 800Mbps back plane and BCC-3-32
>cards.  Unfortunately, I also have old ASI T3 and OC3 cards in the box
>today.  For whatever reason, even under relatively light traffic load,
>the box simply cannot pass traffic without dropping cells.  I'm not sure
>why it does this, and its statistics don't tell me enough.  I've had to
>move customers off of it and on to temporary links direct between equipment.
>
>Everything I've read about the old ASI cards says that they lack cell buffers,
>and that the box does not perform well with traffic patterns that heavily
>utilize specific paths through the switch cell matrix.  To make matters worse,
>I can't upgrade the box because I can't find CWM / StrataView / SVLite anywhere.
>
>To move back to the switched model, I need a switch that works.  I could
>get a BPX 8620 with BCC-4 cards and newer BXM T3/OC3 cards, but I also have an
>opportunity to get a new-in-box Alcatel/Xylan OmniSwitch 9 port with
>recent software on it.
>
>I am querying the list to see if anyone has:
>
>1. Any idea why my BPX-15 sucks (Software 8.2.04!)?
>2. Any idea if the OmniSwitch 9wx is decent/reliable in an ISP environment
>with constant heavy traffic demands between specific ports ?
>3. Any other recommendations on a switch to look at????
>4. Should I just get a 6400 UAC now and use the switch capability on
>the back of it?
>   4a. Can it switch from what appears to be a front OC12 port to the back
>       DS3 ports?
>   4b. Will the switch on the 6400 UAC handle heavy constant load between
>       ports without making the switching matrix into a blocking, cell
>       dropping piece of crap ?
>5. Anything else I'm missing ?
>6. A copy of svlite :)
>
>-c
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