ip address assignment

[bluesea2010]

Hi

Please advise the pros and cons  of  the ip address assignment 

Running OSPF   between access and core and dc . 

Thanks

[balaji.bandi]

High level i do not see any issue here - in related to OSPF p2p address concern.

[Georg Pauwen]

Hello,

as long as you do not use overlapping subnets (which you do not), the IP addressing is fine. What are you 'concerned' about ?

[bluesea2010]

In edge side site 1  i am using 10.0.0.0/16 and site 2 10.1.0.0/16 , my first concern what should be the wlc management address , second thing I would like to do route summarization . Do I really go for vlsm 

Thanks

[balaji.bandi]

my first concern what should be the wlc management address  - you can use any address as long as the AP and Clients can be rechable.

, second thing I would like to do route summarization - Cores should be  already know the full routing table - on edge you can do summary with the area, so they do not need required to know full routing table.

[Georg Pauwen]

Hello,

we don't know anything about the IP addressing of the actual LAN segments. You are only showing the IP addressing used for the links. What do you want to summarize ?

IP address 172.16.6.100/24 is fine for the WLC, since it is not overlapping.

[Joseph W. Doherty]

If you want to do route summarization, and since OSPF route summarization can be done on ABRs, I would suggest using a 10.x.x.x/16 for each OSPF area (not by site).

I'm guessing why you're using 172.16.x.x/16 and 192.168.x.x/16 is so you'll know the former is p2p and the latter DC IPs.  Again, for nice and "tidy" route summarization, I would recommend using, if possible, just one summary route for each OSPF area.  For something like p2p, you might use a particular block of each /16 for those network prefixes.  For your DC, you might also do that or perhaps allocate it its own 10.x.x.x/16 block.  If the latter, you might then have two 10.x.x.x/16s for the ABRs having the DC within it or you might use a 10.x.x.x/15 or /14 for that particular OSPF area.

BTW, at least Cisco's OSFP implementation is quite happy using /31s for your p2p networks.

If you haven't use OSPF ABR summarization before, do insure if using multiple ABRs, that each can get to all the routers in that area.  I.e. with summaries, you can blackhole unreachable networks because the summary doesn't depend on ABR actually being able to reach the interior area destination network.

[bluesea2010]

Hi,

"I'm guessing why you're using 172.16.x.x/16 and 192.168.x.x/16 is so you'll know the former is p2p and the latter DC IPs"

Yes you are correct , This is only to differentiate .( DC I can't change , it is already assigned to devices )

I would recommend using, if possible, just one summary route for each OSPF area.  For something like p2p, you might use a particular block of each /16 for those network prefixes.  For your DC, you might also do that or perhaps allocate it its own 10.x.x.x/16 block

So you are saying 
for p2p assign 10.x.x.x/16
for dc assign 10.x.x.x/16

"For your DC, you might also do that or perhaps allocate it its own 10.x.x.x/16 block. If the latter, you might then have two 10.x.x.x/16s for the ABRs having the DC within it or you might use a 10.x.x.x/15 or /14 for that particular OSPF area"

Sorry I did not understand "If the latter, you might then have two 10.x.x.x/16s" , what "two" subnets are you talking about

Thanks

[Joseph W. Doherty]

Regarding p2p, for example.  Assuming each area has its own /16, all the p2p network might come out of the same (relative) /22 block within the /16.

If you were able to assign your DC its own /16 but the area that contains it also has its own /16, you would need to advertise the two /16s, from that area, or if the two /16s were part of a larger address block, you might just advertise the larger address block.

e.g.

If area was using 10.3.0.0/16 and DC using 10.7.0.0/16 you would need to advertise those two aggregates, but if area was using 10.4.0.0/16 and DC using 10.5.0.0/16 you could advertise 10.4.0.0/15.

[bluesea2010]

@Georg Pauwen 

The lan segment  for site 1 

10.0.0.0/16
10.1.0.0/16
10.2.0.0/16
10.3.0.0/16

and site 2 

10.4.0.0/16
10.5.0.0/16
10.6.0.0/16
10.7.0.0/16

What if I use the 172.16.3.x for wlc management 

And also I continue  172.16.3.x /30 for links  in site 2 also 

Thanks