kwe@bu-cs.BU.EDU (kwe@bu-it.bu.edu (Kent W. England)) (02/10/89)
In article <8902080638.AA14652@SCUBED.ARPA> >hutton@scubed.arpa (Thomas Hutton) writes: >We are soon going to need to connect our three San Diego sites ethernets >via T1 lines. I am interseted in hearing recomendations on various >hardware for doing this. > >Since we need to transfer not only IP traffic but DECNET as well Im assuming >I need to use a bridge vrs a gateway product. One of the things we would >like to do is have a redundent set of circuits: > If you install three bridges, you will need spanning tree or packet loops will result. You will not be able to use any part of the bandwidth of the redundant link. If you install routers, you can use all three links for throughput and for redundancy. If you need IP and DECnet, you can find routers that will route both. If you want bridging too (like LAT, ugh) you can buy a cisco HyBridge which will route IP and DECnet and bridge whatever other protocols you want. I have not yet personally set up a HyBridge, but I read the Rel 7.0 addendum and it looks like a reasonable hybrid. The new cisco hardware is full-ethernet bandwidth, so the old argument about packet switching slowness of routers is now moot. > >I am concerned with the problem of routing loops. I would really > like something >that could while avoiding loop problems, >split the traffic over the links >to optimize the bandwidth of the links. > All modern routing implementations should have no trouble with three links in your configuration. Spanning tree will stop bridge loops, but lose bandwidth, idling one link completely. BTW, are your sites within 4-5 miles line of sight of each other? You could save a lot of money with microwave and you could run full Ethernet bandwidth, too. There are, at last count, three vendors selling such products. Kent England, Boston University