No subject

Melbourne Wireless OSPF areas and IP ranges:
1: 10.10.0.0 -  10.10.15.240    (RGCentral)
2: 10.10.16.0 - 10.10.31.240    (RGWesternPlains)
3: 10.10.32.0 - 10.10.47.240    (RGMaribynong)
4: 10.10.48.0 -  10.10.63.240   (RGInnerNorth)
5: 10.10.64.0 - 10.10.79.240    (Used to be RGDarebin)
6: 10.10.80.0 - 10.10.95.240    (RGNorthEast AKA YarraNorth)
7: 10.10.96.0 - 10.10.111.240   (RGYarraValley)
8: 10.10.112.0 - 10.10.127.240  (RGInnerEast AKA Eastern)
9: 10.10.128.0 - 10.10.143.240  (RGOuterEasternAndFoothills AKA
DandenongFoothills)
10: 10.10.144.0 - 10.10.158.240 (RGSouthern)
11: 10.10.160.0 - 10.10.175.240 (RGPeninsula)

There is now an area 12 which is RGSouthEastern but this is in the
process of being implemented - it doesn't yet appear in LocFinder and it
doesn't have an address range - those out there are currently using
RGSouthern addresses.

These are all /20 ranges (AKA netmask 255.255.240.0).

So all of us in RGSouthern should have this in their ospfd.conf:

router ospf
 ospf router-id 10.10.xxx.xxx
 redistribute connected
 network 10.10.144.0/20 area 0.0.0.10
 passive interface ethX

The passive interface is for any interface you don't want OSPF to add
routes for, such as your internal LAN interface.

Those in RGMaribynong should likewise have this in their ospfd.conf:

router ospf
 ospf router-id 10.10.xxx.xxx
 redistribute connected
 network 10.10.32.0/20 area 0.0.0.3
 passive interface ethX

Someone stop me if this seems all wrong. :)

The two nodes on each end of an RGSouthern-RGMaribynong inter-area link
should both have this in their ospfd.conf:

router ospf
 ospf router-id 10.10.xxx.xxx
 redistribute connected
 network 10.10.32.0/20 area 0.0.0.3
 network 10.10.144.0/20 area 0.0.0.10
 passive interface ethX

Doing it this way means that all nodes in RGSouthern will have a
10.10.32.0/20 entry in their routing tables to represent all nodes in
RGMaribynong.  Likewise all nodes in RGMaribynong will see a
10.10.144.0/20 entry in their tables to represent all possible addresses
in RGSouthern.  This helps to keep routing tables to a reasonable size,
and is especially important if more inter-area links start happening.

That's about the extent of my newfound knowledge of Quagga and OSPF.  My
ospfd.conf used to have 'redistribute connected route-map just-10' but
I've read the docs and I still can't work out what a route-map is
exactly, and what 'just-10' means.  OSPF works with just 'redistribute
connected' so I'm thinking it's best to keep things simple.

I do have a concern that we may need to use different OSPF ABR (area
border router) types - being standard, cisco, ibm and shortcut.  And
also OSPF Area types (normal, stub, not-so-stubby and totally-stubby) -
since the RGSouthern-RGMaribynong link would not be connected via a
backbone there may be a problem, because OSPF tries to send all traffic
from a non-backbone area to the backbone area (area 0.0.0.0).  So
imagine a situation where RGSouthern is connected to a theoretical
backbone and RGMaribynong is not.  The routers in RGSouthern will want
to send their traffic to the backbone, including traffic for
RGMaribynong.

What do people think we should do here?  I'm a fan of keeping configs as
simple as possible - of course if routing breaks with a simple config
then we need to get more complicated and configure different Area and
ABR types.  If this happens then we probably need to work out a way of
notifying everyone if the status of an area or an ABR changes.

This doc briefly explains the issue:
http://www.ietf.org/internet-drafts/draft-ietf-ospf-abr-alt-05.txt

Here's a description of what a 'shortcut' ABR does
http://www.ietf.org/proceedings/00jul/I-D/ospf-shortcut-abr-02.txt

This is a description of the different kinds of OSPF area.
http://www.riverstonenet.com/support/ospf/ospf-areas.htm

Dan


>  I'm a bit of a supporter of doing it right the first time,
considering
> the
> objective of Melb wireless is to make one big network. Using the wrong
> ospf
> area now, only means a lot of rework later on if, or when you, connect
to
> another area. I'd suggest using the correct area from now on and
fixing up
> what you have now.
> 
>  I've got a mate in RGSouther and I'm hoping that we will be able to
link
> up
> real soon now. :)

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