The example in Figure 1 shows two path manager nodes connecting using SNA protocols, or BSC protocols when the "high end" (node name closer to "Z" in the alphabet) initiates the protocol.

┌───────────────────┐                    ┌───────────────────┐
│                   │I──────────────────→│                   │
│                   │                    │                   │
│                   │←──────────────────J│                   │
│     WASH          │                    │     NEWYORK       │
│     The High End  │                    │     The Low End   │
│     (primary)     │                    │     (secondary)   │
│                   │L──────────────────→│                   │
│                   │                    │                   │
│                   │←──────────M───────→│                   │
│                   │                    │                   │
│                   │←──────────N───────→│                   │
└───────────────────┘                    └───────────────────┘

1. WASH attempts to sign on to NEWYORK by sending an I (initial signon) record.
2. NEWYORK responds to WASH by returning a J (response signon) record.
3. WASH responds to NEWYORK by returning an L (concurring signon) record to indicate that both systems will communicate across the established line.
4. When connected, both WASH and NEWYORK send M (add connection) and N (subtract connection) records to each other to share information about their other NJE connections. They also send M records to other path manager nodes to which they are connected to notify them of this connection.

When this connection is dropped by either WASH or NEWYORK, both nodes send N records to any path manager nodes with which they are connected to inform them that the connection no longer exists.

In the BSC case where the "low end" initiates the signon, the "low end" responds to the J record with a K record and the "high end" sends the L record.