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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical DSL frames (was: Jumbo Frames)
-----BEGIN PGP SIGNED MESSAGE----- Bill Woodcock wrote: > This problem is also one that plagues DSL, as many DSLAMs expect to see a > full Ethernet packet, including Ethernet header, inside the frame/atm > packet that comes in from the network. They strip the frame/atm header, > and dump the contents onto the DSL/Ethernet wire. > > If you're using frame relay on the backhaul, a max-length Ethernet packet > with both Ethernet and frame relay headers will obviously exceed the > 1500-byte limit, and get truncated. If you pull the Ethernet header out, > you need to get the DSLAM to generate a new one on the other side, which > many of them verge on not being smart enough to do. > As a small ISP, we've been using Wailan.com boxen, which has both bridging and routing (RIPv2), DHCP and NAT. We turn bridging off, which seemed to fix our problems. However, I've found no documentation on their wire discipline. I'd not thought of using FrameRelay in the backhaul. (You clever fellow!) Instead, I'm trying stringing them together (that is, one of the lines into the DSLAM router is really the upstream to the city POP), putting the DSLAM into one customer site, and then running our own wires from each DSLAM to other customers in the area.... This only works because Wailan allows both 7:7 SDSL and 7:1 ADSL in the same box, and the DSLAM seems to be a special purpose self-contained router. Can you believe that BellSouth wants $2000 for installation and $91 per month to setup an unloaded alarm circuit? -----BEGIN PGP SIGNATURE----- Version: PGP 6.5.1 iQCVAwUBOU7Hmdm/qMj6R+sxAQHNWAP/dLWY3hcXXfY7w4+9gZYVXvXsqvlosK37 ns+7Jj0NOX/otoldVL1b5y6ATlM4ch99gfJMXA9VrIUt3PNaO/LLtfXmERzdNrMt pfBny/1GQqhUbptMtOr8qb6P7c/udgiMC9XQ6wGCZHOx6eMNye8eP9HC9xtMsNo0 YWsKJ0ddFc4= =nS3J -----END PGP SIGNATURE-----
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