HL_OneToRouter - check Hop Limit 1 to Router
Router
HL_OneToRouter.seq [-tooloption ...] -pkt HL_OneToRouter.def
-tooloption : v6eval tool option
See also IH_Router.def
None
Tester Target Tester
(Link0) (Link1)
| | |
|-------------------------->| |
| Echo Request to Link0 | |
| | (no forwarding) |
| | |
|<--------------------------| |
| Neighbor Solicitation | |
| | |
|-------------------------->| |
| Neighbor Advertisement | |
| | |
|<--------------------------| |
| ICMP Error at Link0 | |
| or | |
| ICMP Error at Link1 | |
| | |
v v v
1. Send Echo Request to Link0 2. Wait ICMP Error or NS from Link0 3. If NS received then send NA to Link0, and wait ICMP Error again 4. Receive ICMP Error
Echo Request to Link0 Data is:
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 16
NextHeader = 58 (ICMP)
HopLimit = 1
SourceAddress = Tester Global Address (Link0)
DestinationAddress = Tester Global Address (Link1)
ICMP Echo Request
Type = 128 (Echo Request)
Code = 0
Checksum = (auto)
Identifier = 0xffff
SequenceNumber = 1
PayloadData = {1,2,3,4,5,6,7,8}
PASS: ICMP Error at Link0 Received
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 16
NextHeader = 58 (ICMP)
SourceAddress = Target Global Address (Link0)
DestinationAddress = Tester Global Address (Link0)
ICMP Error
Type = 3 (Time Exceeded)
Code = 0 (hop limit exceeded in transit)
Checksum = (auto)
PayloadData = (Echo Request, HopLimit is 1 or 0)
PASS: ICMP Error at Link1 Received
IPv6 Header
Version = 6
Traffic Class = 0
FlowLabel = 0
PayloadLength = 16
NextHeader = 58 (ICMP)
SourceAddress = Target Global Address (Link1)
DestinationAddress = Tester Global Address (Link0)
ICMP Error
Type = 3 (Time Exceeded)
Code = 0 (hop limit exceeded in transit)
Checksum = (auto)
PayloadData = (Echo Request, HopLimit is 1 or 0)
RFC2460
3. IPv6 Header Format
Hop Limit 8-bit unsigned integer. Decremented by 1 by
each node that forwards the packet. The packet
RFC2463
3.3 Time Exceeded Message
ICMPv6 Fields:
Type 3
Code 0 - hop limit exceeded in transit
Description
If a router receives a packet with a Hop Limit of zero, or a router decrements a packet's Hop Limit to zero, it MUST discard the packet and send an ICMPv6 Time Exceeded message with Code 0 to the source of the packet. This indicates either a routing loop or too small an initial Hop Limit value.
perldoc V6evalTool