IPv6 Troubleshooting

IPV6 Addressing
• 128 bit addresses.
• Simplified header with fewer fields; IPv4 has 12 fields, IPv6 has 5 fields;
• No checksum in the header. This results in more efficient process because in IPv4 the TTL is decremented at each hop, the checksum had to be recalculated at each hop, that is not the case with IPv6.
• No packet fragmentation done by the router, instead an ICMP “packket too big” message is sent to the client. Fragmentation information has been moved to an extension header.

Types of IPv6 Addresses
• Unicast — Send to one interface.
• Multicast — Send to many hosts in a group in the FF00::/8 address range.
• Anycast — Send to the nearest host in a group.

Abbreviate IPv6 Addresses
• Leading zeros in a field can be omitted.
• Contiguous fields containing zeros can be abbreviated with “::”.
• eui-64 addresses use the MAC address for the lower 64 bits of an IPv6 address. The MAC address is split in half and FFFE is placed between the two halves to make the 48 bit MAC into 64 bits, universal/local (U/L) flag (bit 7) in the OUI portion of the address is flipped as well.

Troubleshoot IPv6
sh ipv6 int — Validates the IPv6 and status of interfaces.
sh ipv6 routers — Displays IPv6 router advertisements.
sh ipv6 route — Shows the routing table. DUH.
sh ipv6 protocols — Shows parameters and state of the active IPv6 protocols.
debug ipv6 nd — Debug IPv6 neighbor discovery.
debug ipv6 routing — Display debugging messages for IPv6 routing table and route cache updates.
debug ipv6 packet — Displays the debugging messages for IPv6 packets.

IPv6 Configuration
ipv6 cef
ipv6 unicast-routing
ipv6 address xxxx::xxxx/xxx

OSPFv3
Configure OSPFv3
ipv6 router ospf 6
router-id 10.1.1.10
log-adjacency-changes

interface Tunnel0
no ip address
ipv6 address 2026::34:2/122
ipv6 ospf 6 area 34

Troubleshoot OSPFv3
sh ipv ospf neigh
sh ipv ospf
sh ipv ospf int

sh ipv ospf neigh

R4#sh ipv osp neigh

Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
10.1.1.9          1   FULL/  -        00:00:35    14              Tunnel0

sh ipv ospf

R4#sh ipv ospf 
 Routing Process "ospfv3 6" with ID 10.1.1.10
 SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
 Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 Number of external LSA 0. Checksum Sum 0x000000
 Number of areas in this router is 1. 1 normal 0 stub 0 nssa
 Reference bandwidth unit is 100 mbps
    Area 34
	Number of interfaces in this area is 1
	SPF algorithm executed 3 times
	Number of LSA 8. Checksum Sum 0x03A4B8
	Number of DCbitless LSA 0
	Number of indication LSA 0
	Number of DoNotAge LSA 0
	Flood list length 0

sh ipv ospf int

R4#sh ipv ospf int
Tunnel0 is up, line protocol is up 
  Link Local Address FE80::A01:10A, Interface ID 11
  Area 34, Process ID 6, Instance ID 0, Router ID 10.1.1.10
  Network Type POINT_TO_POINT, Cost: 11111
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:04
  Index 1/1/1, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 3
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1 
    Adjacent with neighbor 10.1.1.9
  Suppress hello for 0 neighbor(s)

RIPng
• IPv6 multicast address FF02::9 is the destination address for RIPng update messages.
• Link-local addresses used for next-hop addresses
• Metric is hop count and 15 is still the maximum, 16 is unreachable.
• Distance-vector

Configure RIPng
To set up a 3560 switch for IPv6 you must first configure the switch database management (SDM) template to one that supprts IPV6. The rest of the configuration is the same on a router and a layer 3 switch.

DSW1(config)#sdm prefer dual-ipv4-and-ipv6 routing
DSW1(config)#^Z
DSW1#wri mem
DSW1#reload
DSW1(config)#ipv6 cef
DSW1(config)#ipv6 unicast-routing 
DSW1(config)#ipv6 router rip RIP_ZONE
DSW1(config-rtr)#int fa0/1
DSW1(config-if)#ipv6 address 2026::2:2/122
DSW1(config-if)#ipv6 rip RIP_ZONE enable

Troubleshoot RIPng
sh ipv6 protocols — What protocols are running on what interfaces.
sh ipv6 rip RIP_ZONE — Show general RIPng information concerning the specific RIP_ZONE.
sh ipv6 rip database — Shows the routes in the RIB.
sh ipv6 rip next-hops — Next hops out of this router as seen by RIPng.

sh ipv6 protocols

 
R4#sh ipv6 protocols 
IPv6 Routing Protocol is "connected"
IPv6 Routing Protocol is "static"
IPv6 Routing Protocol is "ospf 6"
  Interfaces (Area 34):
    Tunnel0
  Redistribution:
    None
IPv6 Routing Protocol is "rip RIP_ZONE"
  Interfaces:
    FastEthernet0/1
    FastEthernet0/0
  Redistribution:
    Redistributing protocol ospf 6 with metric 5

sh ipv6 rip RIP_ZONE

R4#sh ipv6 rip RIP_ZONE
RIP process "RIP_ZONE", port 521, multicast-group FF02::9, pid 195
     Administrative distance is 120. Maximum paths is 16
     Updates every 30 seconds, expire after 180
     Holddown lasts 0 seconds, garbage collect after 120
     Split horizon is on; poison reverse is off
     Default routes are not generated
     Periodic updates 15471, trigger updates 7
  Interfaces:
    FastEthernet0/1
    FastEthernet0/0
  Redistribution:
    Redistributing protocol ospf 6 with metric 5

sh ipv6 rip database

 
R4#sh ipv6 rip database 
RIP process "RIP_ZONE", local RIB
 2026::2:0/122, metric 2
     FastEthernet0/0/FE80::212:D9FF:FEA5:1541, expires in 166 secs

<strong>sh ipv6 rip next-hops</strong>
     
R4#sh ipv6 rip next-hops 
 RIP process "RIP_ZONE", Next Hops
  FE80::212:D9FF:FEA5:1541/FastEthernet0/0 [1 paths]
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