Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!swrinde!ucsd!ucbvax!newcastle.ac.uk!Denis.Russell From: Denis.Russell@newcastle.ac.uk Newsgroups: comp.protocols.tcp-ip Subject: IP over X.25 Message-ID: Date: 4 Oct 90 13:35:48 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 43 I have an interest in routing IP datagrams over an X.25 network, and would like some information on the characteristics actual products (routers) that do this. The kind of completely hypothetical (!) setup that interests me is a set of say 50 to 100 mainly Ethernet LANs connected by a wide-area X.25 network with X.25 speeds in the 9.6kbps-64kbps-2Mbps range. In the worst case one might imagine a permanent 2 * N^2 network of X.25 calls, and clearly some intermediate plan using an hierarchy of routers would be preferable. However, I am primarily interested in an intermediate scenario where the X.25 calls are established and cleared down as required. Clearly the practicality of this this would depend on the traffic pattern - but that is not the primary focus of this query. The primary focus is to find out whether routers that support X.25 as an IP bearer have the right sort of characteristic for such an application. For example, one would require support for a substantial number of such calls (10, 20, 30?), and the automatic clearing down of calls after some inactivity timeout. What speed X.25 is supported (preferably well beyond 64kbps)? Does a router exploit already existing inbound X.25 calls to send outbound datagrams or does traffic always result in two calls, one used in each direction? What other questions are important? As some examples of the clarifications we would value are that we understand that Sunlink supports only 4 X.25 calls by default, but can be configured for any larger number. On the other hand, the calls are never cleared due to inactivity. We don't know whether any routers exploit X.25 in a duplex manner or whether two calls are always/sometimes/never set up. I'll summarise to the list if there is interest in the results. Denis Russell JANET: Denis.Russell@uk.ac.newcastle Computing Laboratory Internet: Denis.Russell@newcastle.ac.uk The University Claremont Road Tel: (+44) 91 222 8243 Newcastle upon Tyne Fax: (+44) 91 222 8232 NE1 7RU Telex: 53 65 4 UNINEW G ENGLAND