T1 NSS's go to "Big NOC in the SKY"

By Ellen Hoffman, Merit

Beginning in mid-February, IBM Customer Engineers began visiting each of the NSFNET sites in order to dismantle router hardware which was used to support the T1 backbone network. This step followed the official turn-off of the circuits in December 1992. The routers, officially termed Nodal Switching Systems (NSSs) and based on IBM/RT(r) technology, were located at each of the original thirteen NSFNET sites as well as in Boston.

Provision for OSI Encapsulation

Some of the IBM RT equipment will have a temporarily-extended life in NSFNET activities as final steps in transitioning from T1 to T3 technologies continue. An RT machine located at each NSFNET site serves as an encapsulation node to provide Connectionless Network Service (CLNS) infrastructure across the backbone. It is anticipated that the ANS backbone nodes will support native CLNS capability later this year, which will allow the RTs to be removed completely. In addition, work continues to transition CA*net connections from the NSS technology. A single RT will be used at each of three sites (Princeton, Cornell, and Seattle) to support ongoing CA*net/NSFNET connectivity.

Gone but not forgotten

Although gone, the T1 network will not be forgotten. To memorialize its place in the growth of networking, one NSS will be donated to the Computer Museum in Boston, MA, to take its place along with other momentos of the digital past.

When first implemented just over four years ago, the T-1 (1.5 Mbps) NSFNET backbone was state-of-the-art for the Internet. Demands for higher speed services along with increasing backbone traffic led to the T-3 (45 Mbps) backbone service implemented over the Advanced Network & Services, Inc. Network (ANSnet). ANS provides the service under subcontract to Merit, which manages NSFNET by cooperative agreement with the National Science Foundation. Under an extension of the agreement, T3 service will continue through April 1994.

For more details on NSFNET technology and engineering, regular monthly reports are available for Anonymous FTP from nic.merit.edu in the directory: /nsfnet/engineering.report.

Taken from The Link Letter, Vol. 6 No. 1, April 1993.