IPv6: From JUNOS
http://ippoint.wordpress.com/2010/11/14/ipv6-from-junos/
IPv6: From JUNOS
November 14, 2010 — ippoint
- Version – 4 bits – set to 0×6
- Class – 1 octet – Used for class of service
- Flow label – 20 bits – Used for maintaining a flow of traffic. Sending host place a unique value. Routers that do not support will ignore or reset to 0×00000.
- Payload length – 2 octets – set the max IPv6 packet size to 65,575 bytes
- Next header – 1 octet –encodes the value of header that follows this header. If there is no other header, it is replaced by protocol field as in IPv4 packet. 6 for TCP. 17 for UDP etc.
- Hop Limit – 1 octet – Same as TTL.
- Source address and destination address– 16 octets each.
- Hop-by-hop options header – value 0
- Routing header – value 43
- Fragment header – value 44
- Destination options header – value 60
- Used to notify other routers along the path about special handling requirement of packet.
- Will be processed by all routers in the path.
- Have next-header, length field and data in TLV format.
- Used for padding the entire packet to 64-bit, router-alert as for RSVP path message.
- Source routing in IPv6 is implemented using this header. Contains list of nodes packet must pass on its way to destination.
- Have next-header, length field, Routing type (0-loose source routing, 1-strict SRC routing), segments left (address left in header) and all intermediate routers address for routing.
- In IPv6, routers will not perform fragmentation. SRC host will determine the maximum MTU it can use to communicate with destination.
- If the packets are larger than path MTU, SRC will fragment the packets and send as multiple packets each containing fragment header.
- It contains fragment offset field – 2 octets – [13 bits is fragment offset : xx : M bit]. If M =0 implies last fragment, and identification field.
- Used to notify destination about packet-handling.
- Currently used for 64-bit boundary.
IPv6 routing protocols:
- New protocol for RIP and OSPF is used. And ISIS and BGP are extended to support IPv6.
- IPv6 routes are stored in ‘inet6.0’ route table.
- RIPng:
- Configure ‘neighbor <interface>’ and ‘export’ policy under [edit protocols ripng].
- OSPFv3:
- Same configuration as for OSPFv3. Configure area, interfaces under [edit protocols ospf3]
- ISIS:
- No Special configuration required. TLV used to advertise IPv6 prefix, when the interface configured with IPv6 address is included in ISIS configuration.
- BGP:
- IPv6 are advertised using Multiprotocol BGP (MBGP).
- Enable ‘family inet6 unicast’ command inside group/neighbor to advertise/receive IPv6.
Sample IPv6 BGP configuration:
root@Juniper> show configuration interfaces em0
unit 0 {
family inet6 {
address FEC0:0:0:1111::2/64;
}
}
root@Juniper> show configuration interfaces lo0
unit 0 {
family inet {
address 1.1.1.1/32;
}
}
root@Juniper> show configuration protocols bgp
group ipv6-external {
type external;
family inet6 {
unicast;
}
peer-as 65020;
neighbor FEC0:0:0:1111::1;
}
root@Juniper> show bgp summary
Groups: 1 Peers: 1 Down peers: 0
Table Tot Paths Act Paths Suppressed History Damp State Pending
inet6.0 2 1 0 0 0 0
Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Damped…
fec0:0:0:1111::1 65020 16 17 0 1 5:16 Establ
inet6.0: 1/2/0
root@Juniper> show route table inet6.0 protocol bgp
fec0:0:0:1111::/64
[BGP/170] 00:03:31, MED 0, localpref 100
AS path: 65020 ?
> to fec0:0:0:1111::1 via em0.0
fec0:5:5:5555::5/128
*[BGP/170] 00:03:31, MED 0, localpref 100
AS path: 65020 ?
> to fec0:0:0:1111::1 via em0.0
root@Juniper> show bgp neighbor
Peer: fec0:0:0:1111::1+179 AS 65020 Local: fec0:0:0:1111::2+63092 AS 65010
Type: External State: Established Flags: <Sync>
Last State: OpenConfirm Last Event: RecvKeepAlive
Last Error: None
Options: <Preference AddressFamily PeerAS Refresh>
Address families configured: inet6-unicast
Holdtime: 90 Preference: 170
Number of flaps: 1
Last flap event: Closed
Error: ‘Open Message Error’ Sent: 0 Recv: 1
Peer ID: 100.100.100.100 Local ID: 1.1.1.1 Active Holdtime: 90
Keepalive Interval: 30 Peer index: 0
BFD: disabled, down
Local Interface: em0.0
NLRI advertised by peer: inet6-unicast
NLRI for this session: inet6-unicast
Peer supports Refresh capability (2)
Table inet6.0 Bit: 10000
RIB State: BGP restart is complete
Send state: in sync
Active prefixes: 1
Received prefixes: 2
Suppressed due to damping: 0
Advertised prefixes: 0
Last traffic (seconds): Received 7 Sent 7 Checked 7
Input messages: Total 19 Updates 1 Refreshes 0 Octets 475
Output messages: Total 20 Updates 0 Refreshes 0 Octets 432
Output Queue[0]: 0
<Other end cisco config>
R0#show run | sec bgp
router bgp 65020
no synchronization
bgp log-neighbor-changes
neighbor FEC0:0:0:1111::2 remote-as 65010
no neighbor FEC0:0:0:1111::2 activate
no auto-summary
!
address-family ipv6
neighbor FEC0:0:0:1111::2 activate
redistribute connected
no synchronization
exit-address-family
R0#show run int fa 0/1
interface FastEthernet0/1
ip address 10.1.2.1 255.255.255.0
duplex auto
speed auto
ipv6 address FEC0:0:0:1111::1/64
end
R0#show run int lo0
interface Loopback0
ip address 2.2.2.2 255.255.255.255
ipv6 address FEC0:5:5:5555::5/128
end