Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 716)

FIGURE 79 Verifying path continuity with immediate neighbor
The table below shows the packet header information for the request and response. The added TRILL
OAM information is shown in bold.
Packet header details with Layer 2 traceroute — first hop TABLE 102
Traceroute request packet header Traceroute reply packet header
Outer L2 DA = B1Outer L2 SA = A1Outer 802.1q
tagOuter etype = TRILLTRILL destination RBridge ID =
CTRILL source RBridge ID = ATRILL flags: TTL = 1
Inner L2 DA = MAC 2Inner L2 SA = MAC 1
Inner 802.1q tagInner etype = 0x800
TOAM Opcode = 5 (request)
Outer L2 DA = B1Outer L2 SA = A1Outer 802.1q
tagOuter etype = TRILLTRILL destination RBridge ID =
ATRILL source RBridge ID = BTRILL flags: TTL = MAX
(63) Inner L2 DA = A1Inner L2 SA = B1
Inner 802.1q tagInner etype = TRILL OAM
TOAM Opcode = 4 (reply)
C reachable
Having successfully exchanged packets with the immediate neighbor (Switch B) and established the
reachability of Switch C, the Layer 2 traceroute feature issues another request with TTL set to 2.
Switch B decrements the TTL count and forwards the packet to Switch C, which returns a response to
Switch A. Refer to the figure below.
Troubleshooting procedures
716 Network OS Administrator’s Guide
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