T1 Scheduled for Dismantling
By Jordan Becker, ANS
Mark Knopper, Merit
Two events involving the ANSnet T3 backbone which provides NSFNET T3 backbone service have been in progress for the past few months. First, due to the reliability of the T3 network, dismantling of the T1 backbone is anticipated by the end of 1992. Second, deployment of new RS/960 FDDI (Fiber Data Distributed Interface) cards has been completed as planned at four targeted sites.
Dismantling the T1 Backbone
At mid-October, two networks remained to be cutover to the ANS T3 backbone: EASInet and CA*Net (Canadian national network). Before the T1 network is taken down, provision must be made for Open Systems Interconnection (OSI) Connectionless Network Protocol (CLNP) support on the T3 network. This will occur with a phased, multi-step migration for support of OSI switching over the T3 network in order to ensure network stability as OSI software support is introduced. Subsequently, the AIX 3.2 operating system and native CLNP switching software will be deployed on T3 routers across the ANSnet backbone.
A T3 connectivity backup plan must also be in place. Currently the T3 ENSS (Exterior Nodal Switching Subsystem) nodes are connected with a single T3 circuit to a CNSS (Core Nodal Switching Subsystem) at an MCI POP (Point of Presence). To allow bypass recovery of the ENSS in the event of a T3 circuit or CNSS failure, each T3 ENSS will be connected to a new T1 circuit which terminates at a different backbone POP CNSS.
New FDDI adapter deployed
Deployment of a new RS960 FDDI network communications adapter for the RISC System/6000 router began early in September. RS960 FDDI interfaces are now running on ENSS's in Palo Alto, CA, San Diego, CA, Pittsburgh, PA, and Champaign, IL. The performance and reliability of these nodes has been very good and plans are in place for further distributions early in 1993.
Taken from The Link Letter, Vol. 5 No. 3, November 1992.