Nortel Networks 3500 Topology enhancements, VT management option on STX equipped OPTera Metro

Operation, administration, and maintenance (OAM) features 2-175

ATAG sequence numbers

ATAG is a numeric transaction identifier similar to CTAG. The ATAG value is automatically generated by a TL1 agent and is used exclusively as a sequence number for autonomous messages. It is a number from 1 to 999999. The first ATAG used is 1 when the agent first initializes or is reset. The ATAG automatically wraps to 1 for the next autonomous message when the previous message is assigned 999999.

Each instance of a Database change (DBCHG), Log (LOG), or Inventory (INVENTORY) event is assigned a unique ATAG value. ATAGs survive warm / cold restarts, circuit pack pulls, and circuit pack swaps. ATAGs do not survive save and restore activities. ATAGs are global to the entire network element (that is, the sequence is continuous and uninterrupted spanning all users and sessions on a network element).

Topology enhancements

OPTera Metro 3500 Release 11.0 introduced the following enhancements to the topology mapping feature:

•a network processor will recognize an adjacent OPTera Metro 3000 network element outside the network processor span of control

•a network processor will recognize an adjacent OPTera Connect DX network element

•the MAC address of an OPTera Connect DX is displayed

In order for a network processor to retrieve a connection to an adjacent network element, there must be an SDCC connection between the network processor’s local shelf and the adjacent neighbor.

VT management option on STX equipped OPTera Metro 3500

OPTera Metro 3500 equipped with STX-192 circuit packs is a cross-connect which operates at STS-1 and higher granularity. When you use STS-managed OPTera Metro 3500 NEs with equipment that supports virtual tributaries (VT), such as OPTera Metro 3000 equipped with VTX-series circuit packs, consider VT management when planning traffic flow and the path originating and terminating points.

This section discusses VT management on subtending UPSR and VT grooming.

VT management on a UPSR

Since the STS-managed OPTera Metro 3500(with STX) does not switch at the VT level, when you provision a connection between two VT-managed OPTera Metro 3000 NEs that pass through STS-managed OPTera Metro 3500, use the same VT and VT group number at the OPTera Metro 3000 endpoints.

Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004