I don't know that you can oversubscribe ATM like you would picture say Frame-Relay or an ISP POP. The PVC's are generally allocated & the bandwidth is usually carved-out. SLA's are generally well defines & the circuits are watched (ATM Probes, NOC, SNMP) when you purchase DS3's & OC links. We turned up new OC's in the South West & the very first symptoms of oversubscription weren't with throughput, but latency. Malfunctioning Apps & network management tell all... Phil ----- Original Message ----- From: nrf To: Sent: Wednesday, May 23, 2001 9:03 PM Subject: Exactly what happens in ATM when QoS cannot be fulfilled? [7:5658] > I am interested in exactly what happens in a real world, ATM WAN > environment, where the ATM has been provisioned from a major telco (AT&T or > MCI, let's say). So let's ignore SVC's and PNNI and that kind of thing, > because hardly any telcos use that stuff anyways, and deal only with PVC's > > For example, let's say I got some routers attached to this ATM cloud, > through PVC's. I have decided to contract for, say, a stringent CBR CoS > because I am running real-time video. > > Now, I would presume that the telco has most likely overprovisioned its ATM > core, in order to earn more revenue, such that the telco can meet its SLA > most of the time, but not all the time. > > So exactly what is the sequence of events when the telco ATM switches are > unable to meet the CoS requirements of the ATM "call"? I would imagine that > traffic-policing and CAC would come into play. But could somebody provide a > precise sequence of events that would occur? Would an error message be seen > on the router? > > Thanx > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=5675&t=5675 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
