RE: RE: How to put interface in OSPF area without

From: Volkov, Dmitry (IDS Canada) (dmitry_volkov@ca.ml.com)
Date: Tue Jul 15 2003 - 18:40:53 GMT-3


Interesting, How did You get that :
"The command "area 49 range <whatever>" creates area 49 LSAs on the router
and this is
the purpose of "area 49" command" ???
I never heard about such interpretation of this command and I always thought
that MAIN and only purpose
of "area range" - to configure route aggregation on the ABRs and/or to
filter inter-area routes
(in case when "not-advertise" on that end)

Anyway it's true - "area X range network mask" creates LSA 1 (on ASBR) and
LSA 1 & 3 (on ABR).

However I don't not agree with your concslusion that LSA 5 (redistributed
static) has any relation to area X (49).
You don't need even to have any redistribution on ABR to generate LSA 1 & 3
if You put "area X range"
(I assume that no any connected interfaces belong to "X")

I don't see any evidence that backbone network on R4 belongs to area 49.

So technically speaking despite LSA 1 for area 49 is created, the
requirement to
"put R4s backbone interface in OSPF area 49" is NOT completed.

I think this requirement is wrong. There is no way to put network into area
without "network" command

Thanks,
Dmitry

area 0 ----(eth0/1)R4(et0/0)-----Backbone

interface Loopback0
 ip address 11.11.11.1 255.255.255.0
 ip ospf network point-to-point
interface Ethernet0/0
 ip address 150.50.10.1 255.255.255.0
interface Ethernet0/1
 ip address 192.168.15.1 255.255.255.0
!
router ospf 1
 log-adjacency-changes
 area 49 range 150.50.10.0 255.255.255.0
 redistribute static subnets
 network 11.11.11.0 0.0.0.255 area 123
 network 192.168.15.0 0.0.0.255 area 0
!
ip route 150.50.10.111 255.255.255.255 Ethernet0/0

            OSPF Router with ID (11.11.11.1) (Process ID 1)

                Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
11.11.11.1 11.11.11.1 426 0x80000002 0x9947 1
192.168.15.15 192.168.15.15 426 0x80000020 0x2EA 1

                Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
192.168.15.15 192.168.15.15 427 0x80000001 0x265B

                Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
11.11.11.0 11.11.11.1 421 0x80000011 0xD612

                Router Link States (Area 49)

Link ID ADV Router Age Seq# Checksum Link count
11.11.11.1 11.11.11.1 431 0x80000002 0xFDFC 0
          
                Summary Net Link States (Area 49)

Link ID ADV Router Age Seq# Checksum
11.11.11.0 11.11.11.1 427 0x80000001 0xF602
192.168.15.0 11.11.11.1 412 0x80000003 0x8313

                Router Link States (Area 123)

Link ID ADV Router Age Seq# Checksum Link count
11.11.11.1 11.11.11.1 437 0x80000001 0x6663 1

                Summary Net Link States (Area 123)

Link ID ADV Router Age Seq# Checksum
192.168.15.0 11.11.11.1 412 0x80000003 0x8313

                Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag
150.50.10.111 11.11.11.1 437 0x80000001 0x102C 0
r4#

r4#sh ip ospf data route

            OSPF Router with ID (11.11.11.1) (Process ID 1)

                Router Link States (Area 0)

  LS age: 463
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 11.11.11.1
  Advertising Router: 11.11.11.1
  LS Seq Number: 80000002
  Checksum: 0x9947
  Length: 36
  Area Border Router
  AS Boundary Router
  Number of Links: 1

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.168.15.15
     (Link Data) Router Interface address: 192.168.15.1
      Number of TOS metrics: 0
       TOS 0 Metrics: 10

          
  LS age: 466
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 192.168.15.15
  Advertising Router: 192.168.15.15
  LS Seq Number: 80000020
  Checksum: 0x2EA
  Length: 36
  Number of Links: 1

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 192.168.15.15
     (Link Data) Router Interface address: 192.168.15.15
      Number of TOS metrics: 0
       TOS 0 Metrics: 10

                Router Link States (Area 49)

  LS age: 472
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 11.11.11.1
  Advertising Router: 11.11.11.1
  LS Seq Number: 80000002
  Checksum: 0xFDFC
  Length: 24
  Area Border Router
  AS Boundary Router
  Number of Links: 0

                Router Link States (Area 123)

  LS age: 482
  Options: (No TOS-capability, DC)
  LS Type: Router Links
  Link State ID: 11.11.11.1
  Advertising Router: 11.11.11.1
  LS Seq Number: 80000001
  Checksum: 0x6663
  Length: 36
  Area Border Router
  AS Boundary Router
  Number of Links: 1

    Link connected to: a Stub Network
     (Link ID) Network/subnet number: 11.11.11.0
     (Link Data) Network Mask: 255.255.255.0
      Number of TOS metrics: 0
       TOS 0 Metrics: 1

> -----Original Message-----
> From: Alexander Arsenyev (GU/ETL)
> [mailto:alexander.arsenyev@ericsson.com]
> Sent: Tuesday, July 15, 2003 12:32 PM
> To: ccielab@groupstudy.com
> Subject: RE: RE: How to put interface in OSPF area without
>
>
> I respectfully disagree. The command "area 49 range
> <whatever>" creates area 49 LSAs on the router, and this is
> the purpose of "area 49" command, not to summarise anything
> out from area 49.
> What I infer from the diagram is that there are just 2
> interfaces on the R4 and "Backbone interface" should be put
> into OSPF process and in area 49. If area 49 already present
> in this router or there are more interfaces You should tell
> us about this. My solution creates LSA type 5 for "Backbone
> interface" and this LSA is present in area 49 though this is
> kind of almost non-existent area since it has no any
> interfaces in it and link count in area 49 router LSA on R4 is 0.
> Nevertheless, I believe if router LSA exists for area 49 it
> means that area itself exists.
>
> Strangely enough, area 49 LSA stay there if even I delete
> "area 49 range" statement and clear ip ospf process, but this
> is not a main problem. The main problem is to create area 49
> without "network" statement and if someone knows better way I
> would love to hear.
>
> Thanks//Cheers
> Alex
>
> -----Original Message-----
> From: Volkov, Dmitry (IDS Canada) [mailto:dmitry_volkov@ca.ml.com]
> Sent: 15 July 2003 17:18
> To: 'polarccie@yahoo.co.uk'
> Cc: ccielab@groupstudy.com; Alexander Arsenyev (GU/ETL)
> Subject: RE: RE: How to put interface in OSPF area without
>
>
> Exactly ! Area range for intra area routes - not for External.
> And there is no way to define area Nr inside
> "Summary-address" command
> So it will not work.
>
>
> Dmitry Volkov
>
> > -----Original Message-----
> > From: polarccie@yahoo.co.uk [mailto:polarccie@yahoo.co.uk]
> > Sent: Tuesday, July 15, 2003 7:27 AM
> > To: ccielab@groupstudy.com
> > Subject: Re: RE: How to put interface in OSPF area without
> >
> >
> > you mean the summary-address here...
> >
> > -----------------------------
> > ...
> > 3) define "area 49 range <net Backbone range>" on R4
> > ..
> >
> >
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