Xref: utzoo comp.protocols.iso:1529 comp.protocols.tcp-ip:14754 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!think.com!snorkelwacker.mit.edu!primerd!tiger1!huston From: huston@prime.com (Steve Huston) Newsgroups: comp.protocols.iso,comp.protocols.tcp-ip Subject: Re: Advantages/Disadvantages Of TCP+Router Vs. Straight X.25 Message-ID: Date: 5 Feb 91 14:24:31 GMT References: <38836@cup.portal.com> Lines: 38 Nntp-Posting-Host: tiger1 Will@cup.portal.com (Will E Estes) writes: >I would like to get opinions on pros and cons for setting up an >Internet. The two setups are: You didn't say what sort of sites you're connecting, but from your mentioning connecting sites to a PDN, I'm thinking you've got clusters of machines, with the clusters connected by X.25 over PDN...if that's a bad assumption, sorry. >1) All sites on the internet have routers that attach to a public >data network, like UUNET's Alternet, and use TCP/IP to communicate >between nodes on the net. To the extent that X.25 might be used >underneath TCP between the routers, this is invisible to the >applications. >2) All sites on the internet connect directly to an X.25 network, >and any client-server applications between two sites are written >directly to an X.25 API or to some software abstraction that is >written on top of X.25. >What are the advantages to either approach? Clearly 2) is going >to be more efficient since you don't have the extra error-checking >of TCP and you don't have the extra data bandwidth of the router >headers being attached to each packet. This advantage aside, are >there any decisive advantages that argue for approach 1)? Approach 1 (TCP) buys you the flexibility of using a standard API (sockets, streams, etc.) while retaining the flexibility of changing/adding to your underlying network technology as your network grows, changes shape, etc. and communications technology improves. You can mix/match non-X.25 network elements with your existing X.25 parts, and your applications just keep working. Steve Huston +1 508 620 2800 ext 3099 Huston@Relay.Prime.COM Prime Computer, Inc. The opinions expressed above are not necessarily those of Prime Computer.