Cell Relay Archive

[Yu Ning <yuning@mindless.com>]

As to UBR service, only PCR is optional,  up to the network side's demand,, and
reference only. According to your deployment, I suggest not thinking reserve bandwidth
for UBR service (in fact no bandwidth reservation provided for UBR.), but reserve bw
for your VOD, or other bandwidth specific service(whether they are CBR, or VBR), then
the left bw can be used by your UBR service (IP best effort), and in fact you can have 
many UBR(for IP) VCs competing the remaining bandwidth, and that's actually what UBR
was originally for (utilizing the remaining bw).

>On Tue, 18 Aug 1998 20:18:40 +0800
>Liping Wang <wanglp@bjaimail.asiainfo.com> wrote:

> 	I use a cisco7513 connect to ATM backbone. The backbone is built
> with several FORE ATM switches, maybe ASX200.
> 	Since cisco7513's PA-A1 card can only support UBR traffic. I have to
> use UBR transfer IP packages between two LANs over the ATM backbone.
> 	The trouble is, the ATM switch uses only one physical interface to
> connect with several access networks, such as IP network, VOD network....The
> switch assigns a PVC for my LAN, but it cannot guarantee any bandwidth since
> I use UBR! Will my traffic be discard if the VOD application with higher
> priority need more bandwidth? 
> 
> 	I think the switch should assign a definite bandwidth when PVC is
> setup. No matter the traffic is UBR or CBR. 
No, CBR has PCR(=SBR); VBR has PCR,SCR,MBS;ABR has PCR,MCR;
and UBR has _none_ :-)
> 
> 	Who can tell me how to get an pipe that has enough and reliable
> bandwidth to interconnect my LANs with cisco PA-A1 and FORE ASX200? 45Mbps
> or 155Mbps is enough.
> 
> 	Thanks.
> 
> 	Wang liping
> 
> 	wlp@bjai.asiainfo.com
> 

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Yu Ning
ATM R&D Center of
BUPT (Beijing U. of Posts&Telecom)
Beijing (ZIP:100876, MBox:147#), P.R.China 
yuning@mindless.com
Ideas reflect view points of my own,:-)
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