At 02:12 PM 6/30/97 -0700, Josh Beck wrote:

Has everyone else been seeing the almost daily UUnet outages recently, does anyone know what the true causes of these have been?

Perhaps this has something to do with it: Glitch slows UUNET to crawl June 23, 1997 Network World If the Internet felt slower than usual last Monday, you were probably a victim of the brownout on UUNET Technologies' network that slowed services in the Northeast. No one is disputing that there was a brownout. But UUNET and Cisco Systems, Inc. - which sold the Internet service provider its routers - are at odds over how it happened. The problem, both sides agree, was a router memory failure. After that, the stories diverge. According to UUNET, the ISP's hubs in Washington, D.C., and Newark, N.J., dropped packets because of a software glitch on its Cisco routers. The hubs are like points-of-presence where UUNET users' traffic is routed to and from the Internet. The routers suffered what the ISP is calling a ``memory leakage.'' Typically, after a router uses a block of memory, it puts the block back into a pool of usable memory. But that is not what happened on UUNET's routers last week. Instead of the memory being usable, it was fragmented, said Alan Taffel, vice president of marketing at UUNET. Large clusters of data that came through the routers could not be handled by the fragmented memory blocks. Once the routers ran out of memory, they automatically reset. UUNET notified Cisco, which sent over a software patch. The software Band-Aid freed up more memory in the routers cache so it would not overload, said Bob Michelet, director of corporate relations at Cisco. The patch is a temporary measure meant to be used until UUNET ups the memory on its routers, he said. UUNET started upgrading the memory on the routers, which Cisco contends was the real culprit. Cisco recommends that its ISP customers use 128M bytes of total memory on their route switch processor boards, Michelet said. UUNET uses 64M-byte memory boards on most, if not all, of its 7,500 routers. UUNET said it never received a recommendation from Cisco concerning memory for its 7,500 routers. ``But clearly, once this event occurred, we discussed the memory issue with Cisco, and we agreed the right course of action would be to upgrade the routing memory to 128M bytesÙ,'' said Jim McManus, vice president of systems engineering at UUNET. Almost every large to midsize ISP uses some Cisco equipment, so should users be concerned? That depends on who answers the question. Cisco claimed UUNET was the only ISP using 64M-byte route switch processor boards. One ISP agrees. Genuity, Inc., Bechtel Enterprises' ISP subsidiary, said it would not run a router with less than 128M bytes of memory. Genuity uses Cisco 7513 routers with fully loaded memory because the routers have to store the routing table for the entire Internet, said Rodney Joffe, chief technology officer at Genuity. Copyright 1997, Network WorldÙ

Josh Beck jbeck@connectnet.com ------------------------------------------------------------------------ CONNECTNet INS, Inc. Phone: (619)450-0254 Fax: (619)450-3216 6370 Lusk Blvd., Suite F-208 San Diego, CA 92121 ------------------------------------------------------------------------