InfiniBand Network Architecture

How Packets Are Normally Routed

Table 31-1 on page 873 illustrates the content of a LID-routed SMP's data payload. After LIDs have been assigned to all ports on CAs and routers and to port 0 on each switch, the port that originates an SMP packet specifies:

• the LID of the destination port in the packet's DLID field and

• its own LID in the packet's SLID field (in case a response is required).

Switches then forward the packet from source to destination by consulting their forwarding tables (which the Master SM set up after it had completed discovery).

This is referred to as a LID-routed SMP.

Table 31-1. LID-Routed SMP MAD Format

Dword		Byte 0	Byte 1	Byte 2	Byte 3
0	Base MAD Header	Base Version = 01h	Management Class = Subn	Class Version = 01h	R	SM Method (see ...