Topology Discovery: Difference between revisions

@@ Line 3: / Line 3: @@
 ==Explicit Protocols==
 ===Cisco Discovery Protocol (CDP)===
+===Link-Layer Discovery Protocol (LLDP)===
+IEEE Standard 802.1AB-2005. It operates directly atop Ethernet, using protocol number 0x88cc, or over SNAP-encoded LLC with the discriminator aa:aa:03:00:00:00. The LLDP multicast destination address is 01:80:c2:00:00:0e.
 ===Link-Local Topology Discovery (LLTD) Protocol===
 A [http://msdn.microsoft.com/en-us/windows/hardware/gg463061.aspx Microsoft protocol] native to Windows Vista and supported on Windows XP via add-on. It operates directly atop Ethernet, using protocol number 0x88D9.
+====LLTD Packet Format====
+{| class="wikitable" border="1"
+|-
+! Field
+! Size
+! Value
+|-
+| colspan="3" align="center" | '''Ethernet header (14 bytes)'''
+|-
+| Destination MAC
+| 6 octets
+|
+|-
+| Source MAC
+| 6 octets
+|
+|-
+| Protocol
+| 2 octets
+| 0x88d9 in [[Endianness|NBO]]
+|-
+| colspan="3" align="center" | '''LLTD Demux Header (4 bytes)'''
+|-
+| Version
+| 1 octet
+| 1
+|-
+| Type of Service
+| 1 octet
+|
+*0: Topology Discovery
+*1: Quick Discovery
+*2: QoS Diagnostics
+|-
+| Reserved
+| 1 octet
+| Must be set to 0 by sender
+Must be ignored by receiver
+|-
+| Function
+| 1 octet
+| Specific to Type of Service values
+|-
+|}
 ==Inferring Topology==
+==See Also==
+* Wireshark's entries for [http://wiki.wireshark.org/LinkLayerDiscoveryProtocol LLDP]
 [[CATEGORY: Networking]]