Frame 7 (110 bytes on wire, 110 bytes captured) Ethernet II, Src: Fujitsus_7f:fd:5f (00:30:05:7f:fd:5f), Dst: IPv6-Neighbor-Discovery_00:00:00 Internet Protocol Version 6 Internet Control Message Protocol v6 Type: 134 (Router advertisement) Code: 0 checksum: 0xe1b3 [correct] Cur hop limit: 64 Flags: 0x00 Router lifetime: 60 Reachable time: 10000 Retrans timer: 10000 ICMPV6 option (Prefix information) Type: Prefix information (3) Length: 32 Prefix length: 64 Flags: 0xe0 onlink = Auto = Router Address = Not site prefix valid lifetime: 86400 Preferred lifetime: 14400 Prefix: 2001:14b8:138:42:: ICMPV6 option (Source link-layer address) Type: Source link-layer address (1) Length: 8 Link-layer address: 00:30:05:7f:fd:5f Figure 3.28 Example: reception of unsolicited router advertisement. Deploying IPv6 in 3GPP Networks its fe80: 5ff: fd5f link local address to ff02: all-nodes on a link multicast address. Even though this is an unsolicited Router Advertisement, our host does welcome it, and uses it, as shown in the trace entry 8 that we will look at in detail shortly. We skip the IPv6 header, as there is nothing new there. The ICMPv6 protocol on the other hand is a rich pool of information. The beginning contains message type, code, and checksum, as discussed earlier. The Router Advertisement specific information starts from the 'Cur hop limit' field, where the router communicates to nodes on the link what Hop Limit they should use (see Section 3.4.3). The 'flags' field is zero, indicating that there are no stateless or stateful DHCPv6 services on the link, the router priority is medium (Section 3.5.6), and it is not an home agent (see explanations in Section 3.4.3). The 'router lifetime' field value is 60, indicating that the router that sent the Router Advertisement can be considered as the default router for the next 60 seconds (see Section 3.4.3). 'Reachable time' tells how long a node should assume that other nodes on the link stay reachable after the node has received reachability confirmation (see also Section 3.4