C H A P T E R  4

Feedback IPv6

IPv6 is a new version of IP which is designed to be an evolutionary step from IPv4. It can be installed as a normal software upgrade in Internet devices and is interoperable with the current IPv4. It has expanded routing and addressing capabilities because of the 128-bit addressing as compared to the 32-bit addressing in IPv4. Its deployment strategy is designed to not have any flag days or other dependencies. IPv6 is designed to run well on high performance networks (for example, extreme-Ethernet, OC-12, ATM, and so on.) and at the same time still be efficient for low-bandwidth networks (such as wireless). In addition, it provides a platform for new Internet functionality that will be required in the near future.

IPv6 includes a transition mechanism, which is designed to allow users to adopt and deploy IPv6 in a highly diffuse fashion and to provide direct interoperability between IPv4 and IPv6 hosts. The IPv6 transition allows the users to upgrade their hosts to IPv6, and the network operators to deploy IPv6 in routers, with very little coordination between the two.

The changes from IPv4 to IPv6 fall primarily into the following categories.


4.1 IPv6 Commands

The list of CLI commands for the configuration of IPv6 is as follows:

4.1.1 ipv6 enable

Enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address. The no form of the command disables IPv6 processing on the interface that has not been configured with an explicit IPv6 address.


ipv6 enable


no ipv6 enable


Mode

Interface Configuration

Defaults

Disabled.

Example

SEFOS(config-if)# ipv6 enable

Notes

IPv6 is enabled on the default VLAN interface.


Related Commands

4.1.2 ipv6 unicast-routing

Enables unicast routing. The no form of the command disables unicast routing.


ipv6 unicast-routing


no ipv6 unicast-routing


Mode

Global Configuration

Defaults

Enabled.

Example

SEFOS(config)# ipv6 unicast-routing


Related Commands

4.1.3 ipv6 address - prefix prefix-len

Configures IPv6 address on the interface. The no form of the command deletes the configured IPv6 address.


ipv6 address prefix prefix-len [{unicast | anycast | eui64}]


no ipv6 address prefix prefix-len [{unicast | anycast | eui64}]


Syntax Description

prefix - IPv6 prefix for the interface.

prefix-len - IPv6 prefix length.

unicast - Unicast type of prefix.

anycast - Anycast type of prefix.

eui64 - Type of prefix where the latter 64 bits are formed from the link layer address.

Mode

Interface Configuration

Defaults

unicast

Example

SEFOS(config-if)# ipv6 address 3333::1111 64 unicast

Notes

The prefix length for eui64 type must be 64.


Related Commands

4.1.4 ipv6 address - ipv6-prefix | prefix-length

Configures IPv6 address on the interface.


ipv6 address {ipv6-prefix | prefix_length} [{unicast | anycast | eui-64 | link-local}]


Syntax Description

ipv6-prefix - IPv6 prefix for the interface.

prefix-length - IPv6 prefix length.

unicast - Unicast type of prefix.

anycast - Anycast type of prefix.

eui64 - Type of Prefix where the latter 64 bits are formed from the link layer address.

link-local - Link local type prefix.

Mode

Interface Configuration

Defaults

unicast

Example

SEFOS(config-if)# ipv6 address 3333::1111/64 unicast

Notes

The prefix length for eui64 type must be 64.


Related Commands

4.1.5 ipv6 - link-local address

Configures the IPv6 link-local address on the interface. The no form of the command deletes the configured IPv6 link-local address.


ipv6 address prefix link-local


no ipv6 address prefix link-local


Syntax Description

prefix - IPv6 Prefix for the interface.

link-local - Type of address.

Mode

Interface Configuration

Example

SEFOS(config-if)# ipv6 address fe80::2222 link-local

Notes

The prefix specified must be a valid link-local prefix.


Related Commands

4.1.6 ipv6 - static routes

Configures static routes. The no form of the command deletes the configured static routes.


ipv6 route prefix prefix-len ([next-hop] {[vlan vlan-id]}) [administrative-distance] [unicast]


no ipv6 route prefix prefix-len ([nex-hop] {[vlan vlan-id]}) [administrative-distance] [unicast]


Syntax Description

prefix - IPv6 prefix of the destination.

prefix-len - Destination prefix length.

next-hop - IPv6 prefix of the next hop that is used to reach the destination network.

vlan - VLAN identifier.

administrative-distance - Metric to reach the destination.

unicast - Unicast type of prefix.

Mode

Global Configuration

Defaults

administrative-distance - 1

unicast

Example

SEFOS(config)# ipv6 route 2111::1111 64 3111::1111

Notes

A route will be configured only when a proper route exists for the next-hop prefix in the route table.


Related Commands

4.1.7 ipv6 - neighbor

Configures a static entry in the IPv6 neighbor cache table. The no form of the command removes the static entry from the IPv6 neighbor cache table.


ipv6 neighbor prefix {vlan vlan-id} mac-address


no ipv6 neighbor prefix {vlan vlan-id} mac-address


Syntax Description

prefix - IPv6 prefix of the neighbor

vlan - VLAN identifier

mac-address - Link layer address of the interface

Mode

Global Configuration

Example

SEFOS(config)# ipv6 neighbor 3333::1111 vlan 1 00:11:22:33:44:55


Related Commands

4.1.8 ipv6 default - hop limit

Defaults hop limit for IPv6 datagrams. The no form of command resets default hop limit for IPv6 datagrams.


ipv6 default-hop limit hop-limit_1-255


no ipv6 default-hop limit


Mode

Global Configuration

Example

SEFOS(config)# ipv6 default-hop limit 100


ipv6 nd suppress-ra

Suppresses IPv6 router advertisement. The no form of the command enables IPv6 router advertisement.


ipv6 nd suppress-ra


no ipv6 nd suppress-ra


Mode

Interface Configuration

Defaults

Router advertisements are suppressed.

Example

SEFOS(config-if)# ipv6 nd suppress-ra


Related Commands

4.1.9 ipv6 nd suppress-ra

Suppresses IPv6 router advertisement. The no form of the command enables IPv6 router advertisement.


ipv6 nd suppress-ra


no ipv6 nd suppress-ra


Mode

Interface Configuration

Defaults

Router advertisements are suppressed.

Example

SEFOS(config-if)# ipv6 nd suppress-ra


Related Commands

4.1.10 ipv6 nd managed-config flag

Sets the managed-config flag which allows the host to use DHCP for address configuration. The no form of the command resets the managed-config flag which in turn does not allow the host to use DHCP for address configuration.


ipv6 nd managed-config flag


no ipv6 nd managed-config flag


Mode

Interface Configuration

Example

SEFOS(config-if)# ipv6 nd managed-config flag


Related Commands

4.1.11 ipv6 nd other-config flag

Sets the other-config flag, which allows the host to use DHCP for other stateful configuration. The no form of the command resets the other-config flag, which in turn does not allow the host to use DHCP for other stateful configuration.


ipv6 nd other-config flag


no ipv6 nd other-config flag


Mode

Interface Configuration

Example

SEFOS(config-if)# ipv6 nd other-config flag


Related Commands

4.1.12 ipv6 hop-limit

Configures the maximum hoplimit for all IPv6 packets originating from the interface and the configured hop limit is also used in router advertisement packet current hop limit field. The no form of the command resets the hop limit to the default value for all IPv6 packets originating from the interface and also the value in the router advertisement packet current hop limit field is reset to the default value.


ipv6 hop-limito-limit_0-255


no ipv6 hop-limit


Mode

Interface Configuration

Defaults

64

Example

SEFOS(config-if)# ipv6 hop-limit 100


4.1.13 ipv6 nd ra-lifetime

Sets the IPv6 router advertisement lifetime.


ipv6 nd ra-lifetime seconds_0-9000


Mode

Interface Configuration

Defaults

1800 seconds.

Example

SEFOS(config-if)# ipv6 nd ra-lifetime 1000

Notes

The ND RA lifetime value must be greater than or equal to the RA interval.


Related Commands

4.1.14 ipv6 nd dad attempts

Sets the number of duplicate address detection attempts. The no form of the command resets the duplicate address detection attempts to its default value.


ipv6 nd dad attempts number-of-attempts_1-10


no ipv6 nd dad attempts


Mode

Interface Configuration

Defaults

1

Example

SEFOS(config-if)# ipv6 nd dad attempts 5


Related Commands

4.1.15 ipv6 nd reachable-time

Sets the advertised reachability time. The no form of the command resets the advertised reachability time to default value.


ipv6 nd reachable-time seconds_0-3600 | msec miliseconds_0-3600000


no ipv6 nd reachable-time


Mode

Interface Configuration

Defaults

30

Example

SEFOS(config-if)# ipv6 nd reachable-time 500


Related Commands

4.1.16 ipv6 nd ns - interval

Sets the advertised retransmission time. The no form of the command resets the advertised retransmission time to default value.


ipv6 nd ns-interval retranmission-time-miliseconds_1000-3600000


no ipv6 nd ns-interval


Mode

Interface Configuration

Example

SEFOS(config-if)# ipv6 nd ns-interval 1000


Related Commands

4.1.17 ipv6 nd ra-mtu

Sets router advertisement MTU optional value. The value ranges between 1280 and 1500. The no form of command resets the router advertisement MTU option value to the default value.


ipv6 nd ra-mtu router-advertisement-MTU


no ipv6 nd ra-mtu


Mode

Interface Configuration

Example

SEFOS(config-if)# ipv6 nd ra-mtu 1400


Related Commands

4.1.18 ipv6 nd ra-interval

Sets the IPv6 router advertisement interval. The no form of the command resets the IPv6 Router Advertisement interval to its default value.


ipv6 nd ra-interval maximum-interval-seconds_4-1800 [minimum-interval-seconds_3-1350]


no ipv6 nd ra-interval


Syntax Description

minimum-interval-seconds_3-1350 - Minimum router advertisement interval time in seconds.

maximum-interval-seconds_4-1800 - Maximum router advertisement interval time in seconds.

Mode

Interface Configuration

Defaults

600 seconds.

Example

SEFOS(config-if)# ipv6 nd ra-interval 200


Related Commands

4.1.19 ipv6 nd prefix

Configures the prefix to be advertised in IPv6 router advertisement. The no form of the command removes the prefix from the IPv6 router advertisement.


ipv6 nd prefix {prefix-addr prefix-len | default} [{{valid-lifetime> | infinite | at var-valid-lifetime} {preferred-lifetime | infinite | at var-preferred-lifetime} | no-advertise}] [off-link] [no-autoconfig]


no ipv6 nd prefix {prefix-addr prefix-len | default}


Syntax Description

prefix-addr - IPv6 prefix to be advertised.

prefix-len - Length of the configured prefix.

default - Changes the default value of the rest of the parameters.

valid-lifetime - Sets the valid lifetime value for the prefix.

infinite - Sets the infinite valid lifetime value for the prefix.

at - Sets the variable valid lifetime value for the prefix.

preferred-lifetime - Sets the preferred lifetime value for the prefix.

infinite - Sets the infinite Preferred lifetime value for the prefix.

at - Sets the variable valid lifetime value for the prefix.

no-advertise - Sets the No-Advertise flag.

off-link - Sets the off-link flag.

no-autoconfig - Sets the no-autoconfig flag.

Mode

Interface Configuration

Defaults

RA valid-lifetime - 25,9200 seconds.

RA preferred-lifetime - 60,4800 seconds.

Example

SEFOS(config-if)# ipv6 nd prefix 3333::1111 64 500 400

Notes

valid-lifetime must be greater than or equal to preferred-lifetime.


Related Commands

4.1.20 ping ipv6

Sends IPv6 echo messages.


ping ipv6 prefix [data hex-str] [repeat count] [size value] [anycast] [source {vlan vlan-id | source-prefix}] [timeout seconds_1-100]


Syntax Description

prefix - IPv6 Destination prefix.

data - Data to be sent in ping message.

repeat - Number of ping messages.

size - Size of the ping message.

anycast - Type of prefix.

source - Source interface of the ping message can be as follows:

  • vlan
  • source-prefix

timeout - Duration to wait for the reply.

Mode

Privileged EXEC

Defaults

data - a5a5

repeat count - 5

size - 100 bytes.

timeout - 5 seconds.

Example

SEFOS# ping ipv6 3333::1111 data a6b6


4.1.21 debug ipv6

Enables IPv6 trace. The no form of the command disables IPv6 trace.


debug ipv6 {IP6 | ICMP | UDP6 | ND | PING6}


no debug ipv6


Syntax Description

IP6 - IP6 trace.

ICMP - ICMP trace.

UDP6 - UDP6 trace.

ND - Neighbor discovery trace.

PING6 - PING6 trace.

Mode

Privileged EXEC

Defaults

Disabled.

Example

SEFOS# debug ipv6 IP6


4.1.22 traceroute

Traces route to the destination.


traceroute [ipv6 prefix]


Syntax Description

ipv6 - IPv6 destination prefix.

Mode

Privileged EXEC

Example

SEFOS# traceroute ipv6 4444::1111


4.1.23 clear ipv6 neighbors

Removes all the entries in the IPv6 neighbor table.


clear ipv6 neighbors


Mode

Privileged EXEC

Example

SEFOS# clear ipv6 neighbors


Related Commands

4.1.24 clear ipv6 traffic

Removes all the entries in the IPv6 traffic table.


clear ipv6 traffic


Mode

Privileged EXEC

Example

SEFOS# clear ipv6 traffic


Related Commands

4.1.25 clear ipv6 route

Removes all the entries in IPv6 route table.


clear ipv6 route


Mode

Privileged EXEC

Example

SEFOS# clear ipv6 route


Related Commands

4.1.26 show ipv6 interface

Displays the IPv6 interfaces.


show ipv6 interface [{vlan vlan-id}[prefix]]


Syntax Description

vlan - VLAN identifier.

prefix - Prefix information.

Mode

Privileged EXEC

Example

SEFOS# show ipv6 interface vlan 1 prefix

Codes: A - Address , P - Prefix-Advertisement

D - Default , N - Not Advertised

 

AD 2222:: 64 [LA] Valid lifetime 2592000 , Preferred lifetime 604800

 

AD 2223:1:2:3:: 64 [LA] Valid lifetime 2592000 , Preferred lifetime 604800

 

P 3333:: 64 [LA] Valid lifetime 700 , Preferred lifetime 600

 

PD 3334:: 64 [LA] Valid lifetime 2592000 , Preferred lifetime 604800

 

PN 3335:: 64 [] Valid lifetime 2592000 , Preferred lifetime 604800

 

SEFOS# show ipv6 interface

vlan1 is up, line protocol is up

IPv6 is Enabled

 

Link local address:

fe80::201:2ff:fe03:405

Global unicast address(es):

 

Not Configured.

Joined group address(es):

ff02::1

 

ff02::2

ff02::1:ff03:405

 

MTU is 1500

ICMP redirects are enabled

 

ND DAD is enabled, Number of DAD attempts: 1

ND router advertisement is enabled


Related Commands

4.1.27 show ipv6 route

Displays the IPv6 routes.


show ipv6 route


Mode

Privileged EXEC

Example

SEFOS# show ipv6 route

 

IPv6 Routing Table - 4 entries

Codes : C - Connected, S - Static

O - OSPF, R - RIP, B - BGP

C 2222::/64 [1/1]

via ::, vlan1

C 2223:1:2:3::/64 [1/1]

via ::, vlan1

S 4444::/64 [1/20]

via 2222::2222, vlan1

S 4445::/64 [1/20]

via 2222::2222, vlan1


Related Commands

4.1.28 show ipv6 route summary

Displays the summary of IPv6 routes.


show ipv6 route summary


Mode

Privileged EXEC

Example

SEFOS# show ipv6 route summary

IPv6 Routing Table Summary - 4 entries

2 Connected, 2 Static, 0 RIP, 0 BGP, 0 OSPF

Number of prefixes:

/64: 4


Related Commands

4.1.29 show ipv6 neighbors

Displays the IPv6 neighbour cache entries.


show ipv6 neighbors


Mode

Privileged EXEC

Example

SEFOS# show ipv6 neighbors

 

IPv6 Address Age Link-layer Addr State Interface

 

5555::1111 58 00:11:22:33:44:55 Static vlan1

5556::1111 58 11:22:33:44:55:66 Static vlan1


Related Commands

4.1.30 show ipv6 traffic

Displays the IPv6 ICMP and UDP statistics.


show ipv6 traffic [interface {vlan vlan-id | tunnel tunnel-id | interface-type if-num}] [hc]


Syntax Description

vlan-id - Vlan identifier.

tunnel-id - Tunnel identifier.

interface-type - Interface type.

interface-id - Interface identifier.

hc - High counters (64-bit).

Mode

Privileged EXEC

Example

SEFOS# show ipv6 traffic

 

IPv6 Statistics

***************

0 Rcvd 0 HdrErrors 0 TooBigErrors

0 AddrErrors 0 FwdDgrams 0 UnknownProtos

0 Discards 0 Delivers 1 OutRequests

0 OutDiscards 0 OutNoRoutes 0 ReasmReqds

0 ReasmOKs 0 ReasmFails

0 FragOKs 0 FragFails 0 FragCreates

0 RcvdMCastPkt 1 SentMcastPkts 0 TruncatedPkts

0 RcvdRedirects 0 SentRedirects

 

0 InOctets 0 InNoRoutes 0 OutFwdDatgrms

0 OutFrgRqds 1 OutTrnsmit 64 OutOctets

0 InMcstOctets 24 OutMcastOctets 0 InBcstPkts

0 OutBcstPkts 0 DiscntTime 1000 RefrshRate

 

ICMP Statistics

***************

 

Received :

0 ICMPPkts 0 ICMPErrPkt 0 DestUnreach 0 TimeExcds

0 ParmProbs 0 PktTooBigMsg 0 ICMPEchoReq 0 ICMPEchoReps

0 RouterSols 0 RouterAdv 0 NeighSols 0 NeighAdv

0 Redirects 0 AdminProhib 0 ICMPBadCode

Sent :

0 ICMPMsgs 0 ICMPErrMsgs 0 DstUnReach 0 TimeExcds

0 ParmProbs 0 PktTooBigs 0 EchoReq 0 EchoReply

0 RouterSols 0 RouterAdv 1 NeighSols 0 NeighborAdv

0 RedirectMsgs 0 AdminProhibMsgs

 

UDP statistics

**************

Received :

0 UDPDgrams 1 UDPNoPorts 0 UDPErrPkts

Sent :

0 UDPDgrams

 

SEFOS# show ipv6 traffic interface vlan 1

 

IPv6 Statistics for interface vlan1

-------------------------------------

 

0 Rcvd 0 InOctets 0 HdrErrors

0 InNoRoutes 0 AddrErrors 0 UnknownProtos

0 TruncatedPkts 0 FwdDatagrms 0 ReasmReqds

0 ReasmOKs 0 ReasmFails 0 Discards

0 Delivers 0 OutRequests 0 OutFwdDgrms

0 OutDiscards 0 FragReqds 0 FragOKs

0 FragFails 0 FragCreates 0 OutTrnsmits

0 OutOctets 0 InMcstPkts 0 InMcstOctets

0 OutMcstPkts 0 OutMcstOctets 0 InBcstPkts

0 OutBcstPkts 0 DiscntTime 1000 RefrshRate

 

SEFOS# show ipv6 traffic hc

 

IPv6 Statistics

***************

0 InRcvs 0 InOctets 0 InFwdDgrms

0 InDelivers 2 OutRequests 0 OutFwdDgrms

2 OutTrnsmits 128 OutOctets 0 InMcstPkts

0 InMcstOctets 2 OutMcstPkts 48 OutMcstOctets

0 InBcast 0 OutBcast

 

UDP statistics

**************

0 HC InDatagrams 0 HC OutDatagrams


 

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