From: Alexander Arsenyev (GU/ETL) (alexander.arsenyev@ericsson.com)
Date: Wed Jul 16 2003 - 12:52:16 GMT-3
The documented purpose of "area <number> range <whatever>" is as per Your post below.
In the context of Your task I used it to create area 49 LSAs on router and that is the
purpose of "area 49 range" command on R4.
I have to respectfully disagree second time regarding Type 5 LSAs. Put is this way -
if R4 has only 2 interfaces in 2 areas (o0 and 49) then it's impossible to determine that prefix covering "net Backbone" (or part of it) is coming from area 49. However, if You delete area 0 on R4 this prefix will still stay in R4 LSA database and logically speaking it is coming from area 49 because there will be no other area!
Same happens if You add one more interface on R4, assign it to area 49 and establish adjacency with some other router(s) via this interface. Then delete area 0 on R4 and display LSA database on adjacent router(s). If you see "net Backbone" there - Your task is complete: there is one and only area 49 on R4 and it contains "net Backbone" (or part of it, it depends on static routes configured on R4).
Interestingly, I've just thought that it is possible to propagate whole "net Backbone" by the way of multiple specific static routes redistributed into OSPF - in the extreme case it could be multiple host routes. Referring to Your example below, it could be 254 routes of sort "ip route 150.50.10.$x 255.255.255.255 eth0/0" where x is in range 1...254.
Thanks//Cheers
Alex
-----Original Message-----
From: Volkov, Dmitry (IDS Canada) [mailto:dmitry_volkov@ca.ml.com]
Sent: 15 July 2003 22:41
To: Alexander Arsenyev (GU/ETL)
Cc: ccielab@groupstudy.com
Subject: RE: RE: How to put interface in OSPF area without
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
This archive was generated by hypermail 2.1.4 : Wed Aug 06 2003 - 06:52:41 GMT-3