It was something that came up years ago on where would peering go if traffic levels kept the growth rate exponential. Problem is that while the equipment vendors use "standard" channel frequencies. The implementation (ie protocols) is completely different. While both companies may have DWDM equipment they must hand off standard 1310nm. While working on designs for Bellsouth Mix, we really wanted to extend DWDM directly to the customers. At the very least we hypothesized that with a colo we could see a benefit to DWDM cross-connects (ie intra-node, hair-pinning) however we quickly ran into the vendor issue. If you approach the vendors, the incumbents have no desire to open up their technology since they feel they already "own" the customer base. New companies such as Sycamore or ONI have to find ways to reverse engineer without breaking the law or getting sued. They then run the risk of having this engineering break during an software upgrade to the incumbent's equipment. Sycamore's fix product for example shot DWDM waves using the nortel upgrade port. So u could use sycamore's cheaper equipment to add capacity to your network. They shot at different wavelengths to the nortel gear and therefore caused no problems to the existing network. Nortel was not amused since they would have preferred to sell much for expensive waves. So at the MIX even though we had DWDM throughout the network, we were handing off 1310 to customers. If they did buy similar gear we could have extended the DWDM directly to them. We also could allow for CNM (customer network management) which would allow the customer to control the waves they "owned" on our network. It would seem logical at some point that carriers need to put pressure on their vendors to not only standardize on channels and frequencies but also on a common inter-vendor transport protocol. Treating each DWDM wave as a VPN (or VLAN) for peering btw specific peers makes sense for growth. dave At 16:04 -0700 1/6/03, Pete Kruckenberg wrote:
How common are DWDM interconnects between networks (carriers)?
Is DWDM considered a reliable/scalable/operable carrier interconnection technology?
Is multi-vendor DWDM (whether internal to the network or for carrier interconnection) practical or sensible, especially for carrier/network interconnection? Many vendors proclaim interoperability, but does that work in the real world?
Pete.
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