Cisco extends SNA support

Cisco Systems Canada Co.’s SNA Switching Services allows firms to more efficiently map SNA traffic onto IP networks, according to Cisco officials.

Released in September, SNA Switching Services ships as part of IOS release 12.0(5)XN and will be orderable sometime during the fourth quarter of 1999 as part of Cisco IOS release 12.1.

Prior to the release of SNA Switching Services, users could transport SNA over IP using Data Link Switching (DLSw) Plus, said Stephen Downing, a systems engineer with Cisco Canada in Toronto.

“This is basically a more integrated solution where you do advanced peer-to-peer networking (APPN) over IP and you can talk directly to the mainframes,” he said.

SNA Switching Services is based on IBM’s Enterprise Extender software, which uses IBM SNA technologies APPN and High Performance Routing (HPR)to boost the performance of SNA networks.

The product works by placing a hybrid SNA-IP header on an SNA packet. Instead of a TCP header, the packet gets a User Datagram Protocol (UDP)-IP header. An IP address assigned to the packet will be associated with a destination SNA address. When the packet arrives at a local router with SNA Switching Services, the UDP address is stripped off and the SNA packet is sent on to its ultimate destination.

Downing said SNA Switching Services reduces the large amount of broadcast traffic typically associated with an SNA network.

Dan McLean, an analyst with IDC Canada Ltd. in Toronto, noted there is still a significant installed base of SNA and it makes sense for a large networking firm such as Cisco to help these SNA users migrate their SNA traffic onto IP networks. Surveys of U.S. enterprises that have or had SNA networks have shown that approximately one third of companies still use pure SNA environments, approximately one third have made the conversion from SNA to IP and the remaining third probably have some SNA being converted to or encapsulated in IP, McLean said.

Downing said Cisco will continue to enhance its SNA to IP offerings, especially now that Cisco has access to intellectual assets associated with IBM’s former network hardware division.

“A lot of customers see there’s still a lot of life left in SNA and there are a lot of changes going on and they want to continue using SNA networks,” he said. “But they want to leverage multi-service IP networks at the same time.”

Cisco Canada can be reached at or at 1-800-553-6387.