OSPF again
1. Network types
- broadcast
- non broadcast
- point-to-point
- point-to-multipoint
- point-to-multipoint non broadcast
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2. What about the area types? | |||||||||||||||||||||||||||
| Yes, the areas are the same |
- backbone
- regular
- stub
- totally stub
- not so stubby
- totally nssa
At this point, this post look like an unnecessarily character mass about OSPFv3, but...
3. Differences
The 1st main difference between the two protocol is the transport:
OSPFv3 use IPv6 to make adjacency metween the routers in: ff02::5 (ff02::6 DR/BDR) ipv6 multicast address, in case of non-broadcast scenarios you need to configure the link-local ipv6 address as with the neighbor statement.
The 2nd main difference is the LSAs:
Is there any new LSA type?
Yes in case of OSPFv3 the following LSA types exist:
Type
| 0x0008 | Link-local summary |
| 0x2009 | Intra-Area Prefix |
Here is a table from the differences of OSPFv2 and v3 and the RFCs:
| OSPFv3 LSA Type | OSPFv3 LSA Name (RFC 5340) | OSPFv3 TLVs (RFC 8362) | OSPFv2 LSA Type | OSPFv2 LSA Name | differences |
| 0x2001 | Router | Router-Link TLV | (RFC2328) 1 | Router | contain only adjacency topology information |
| 0x2002 | Network | Attached-Routers TLV | (RFC2328) 2 | Network | contain only adjacency topology information |
| 0x2003 | Inter-Area Prefix | Inter-Area-Prefix TLV | (RFC2328) 3 | Network Summary | |
| 0x2004 | Inter-Area Router | Inter-Area-Router TLV | (RFC2328) 4 | ASBR Summary | |
| 0x4005 | AS-External | External-Prefix TLV | (RFC2328) 5 | AS-External | |
| 0x2006 | Group Membership | Intra-Area-Prefix TLV | (RFC2328) 6 | Group Membership | unused / deprecated |
| 0x2007 | Type-7 LSA | IPv6 Link-Local Address TLV | (RFC2328) 7 | NSSA External | |
| 0x0008 | Link-local summary | IPv4 Link-Local Address TLV | used for advertise link-local address | ||
| 0x2009 | Intra-Area Prefix | (RFC5250) opaque 9 | used for advertise prefix | ||
| (RFC5250) opaque 10 | |||||
| (RFC5250) opaque 11 |
If you do not understand the basics of IPv6, please google it.
Why so IPv6 is important to SPs? Why an other version of OSPF may configured in the a SP network?
In short:
because it need for the capability of dual-stack.
In a longer answer:
The public IPv4 is sold out. (Mostly, but there some institute who find /23 prefixes which are not used yet), so the SPs has to be ready for IPv6 routing on BGP and IGP too. (It is really a long story for this soo leave this question in open).
OSPFv2 and OSPFv3 are not compatible with each other, because:
- They use different IP version for transport
- The headers are different
- LSAs and LSDBs, also LSUs are contain different information
What about the IOS-XE and IOS-XR configurations?
The main difference between the two platform is that IOS-XE support both IPv4 and IPv6 AFs (address family) opposite the in the IOS-XR only the IPv6 is supported.
In a case of IOS-XE the configuration method can be the following:
!!!!!!!ipv6 unicast-routing !!!!!!!! #Yes you need configure that router support the IPv6 routing capabilities.
In global configuration mode:
ipv6 router ospf $process_id
router-id $Lo0_ip_address
!
interface Gi$x
ipv6 enable
ipv6 ospf 1 area $area_id
!
or if you would like to use the IPv4 AFs
router ospfv3 $process_id
router-id $Lo0_ip_address
address-family ipv4 unicast
address-family ipv6 unicast
interface Gi$x
ospfv3 $process_id area $area_id ipv4
ospfv3 $process_id area $area_id ipv6
On IOS-XR only the router statement is available:
router ospfv3
router-id $router_id
!
area 0
!
interface Gi0/0/0/$x
!
!
Do not forget in IOS-XR to commit your configuration.
I think I finished with the OSPF topic... Oh wait what about the authentication? Oh J.sus f.ck cr.st!
Ok, let us talk about that in the next post!
See yo!