On Wed, Feb 25, 2004 at 09:44:51AM -0800, David Meyer wrote:
Jared,
I keep hear of Frame-Relay and ATM signaling that is going to happen in large providers MPLS cores. That's right, your "safe" TDM based services, will be transported over someones IP backbone first. This means if they don't protect their IP network, the TDM services could fail. These types of CES services are not just limited to Frame and ATM. (Did anyone with frame/atm/vpn services from Level3 experience the same outage?)
Is your concern that carrying FR/ATM/TDM over a packet core (IP or MPLS or ..) will, via some mechanism, reduce the resilience of the those services, of the packet core, of both, or something else?
I'm saying that if a network had a FR/ATM/TDM failure in the past it would be limited to just the FR/ATM/TDM network. (well, aside from any IP circuits that are riding that FR/ATM/TDM network). We're now seeing the change from the TDM based network being the underlying network to the "IP/MPLS Core" being this underlying network. What it means is that a failure of the IP portion of the network that disrupts the underlying MPLS/GMPLS/whatnot core that is now transporting these FR/ATM/TDM services, does pose a risk. Is the risk greater than in the past, relying on the TDM/WDM network? I think that there could be some more spectacular network failures to come. Overall I think people will learn from these to make the resulting networks more reliable. (eg: there has been a lot learned as a result of the NE power outage last year).
We're at (or already past) the dangerous point of network convergence. While I suspect that nobody directly died as a result of the recent outage, the trend to link together hospitals, doctors and other agencies via the Internet and a series of VPN clients continues to grow. (I say this knowing how important the internet is to the medical community, reading x-rays and other data scans at home for the oncall is quite common).
Again, I'm unclear as to what constitutes "the dangerous point of network convergence", or for that matter, what constitutes convergence (I'm sure we have close to a common understanding, but its worth making that explicit). In any event, can you be more explicit about what you mean here?
Transporting FR/ATM/TDM/Voice over the IP/MPLS core, as well as some of the technology shifts (VoIP, Voice over Cable, etc..) are removing some of the resiliance from the end-user network that existed in the past. I think that most companies that offer frame-relay which also have a IP network are looking at moving their frame-relay on to their IP network. (I could be wrong here clearly). This means that overall we need to continue to provide a more reliable IP network than in the past. It is critically important. I think that Pete Templin is right to question peoples statements that "nobody died because of a network outage". While I think that the answer is likely No, will that be the case in 2-3 years as Qwest, SBC, Verizon, and others move to a more native VoIP infrastructure? A failure within their IP network could result in some emergency calling (eg: 911) not working. While there are alternate means of calling for help (cell phone, etc..) that may not rely upon the same network elements that have failed, some people would consider a 60 second delay as you switch contact methods too long and an excessive risk to someones health. I think it bolsters the case for personal emergency preparedness, but also spending more time looking at the services you purchase. If you are relying on a private frame-relay circuit as backup for your VPN over the public internet, knowing if this is switched over an IP network becomes more important. (I know this is treading on a few "what if" scenarios, but it could actually mean a lot if we convert to a mostly IP world as I see the trend). - jared -- Jared Mauch | pgp key available via finger from jared@puck.nether.net clue++; | http://puck.nether.net/~jared/ My statements are only mine.