Some more informations :
LSA for 0.0.0.0 (using summary-address) :
CustomerA#sh ip ospf database external
OSPF Router with ID (192.168.254.254) (Process ID 1)
Type-5 AS External Link States
LS age: 5
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 192.168.254.254
LS Seq Number: 80000001
Checksum: 0x2A22
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
CustomerA#sh ip ospf database external
OSPF Router with ID (192.168.254.254) (Process ID 1)
Type-5 AS External Link States
Delete flag is set for this LSA
LS age: MAXAGE(3600)
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 192.168.254.254
LS Seq Number: 80000002
Checksum: 0x301B
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 16777215
Forward Address: 0.0.0.0
External Route Tag: 1
LSA for 4.0.0.0 & 8.0.0.0 summary routes :
CustomerA#sh ip ospf database external
OSPF Router with ID (192.168.254.254) (Process ID 1)
Type-5 AS External Link States
LS age: 11
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 4.0.0.0 (External Network Number )
Advertising Router: 192.168.254.254
LS Seq Number: 80000001
Checksum: 0xEC5E
Length: 36
Network Mask: /6
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
LS age: 11
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 8.0.0.0 (External Network Number )
Advertising Router: 192.168.254.254
LS Seq Number: 80000002
Checksum: 0xAA9F
Length: 36
Network Mask: /5
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
LSA 0.0.0.0 using default-originate command -> works fine
CustomerA#sh ip ospf database external
OSPF Router with ID (192.168.254.254) (Process ID 1)
Type-5 AS External Link States
LS age: 13
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 192.168.254.254
LS Seq Number: 80000001
Checksum: 0x3C0F
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 1
So there's no difference, I just saw that using summary-address, the LSA
0.0.0.0 as an external route tag set to 0 and set to 1 when it is aged out.
I done the same test using a cisco 2500 router with IOS 12.2, and it's the
same, LSA is prematurely aged out when using summary-address command.
Thanks for the help.
Stephane
""Stephane LITKOWSKI"" a icrit dans le message de news:
[EMAIL PROTECTED]
> Hi all,
>
> I tried to use the "summary-address" OSPF command to summarize learned BGP
> routes to a default summary route (0/0) and it seems that it doesn't work.
>
> (fake BGP routes) ----- router A ------------ 1.0.0.0/32 (OSPF) ---------
> router B
>
>
> Router A :
> --------------
>
> router ospf 1
> log-adjacency-changes
> summary-address 0.0.0.0 0.0.0.0
> redistribute bgp 1 subnets
> network 1.0.0.0 0.255.255.255 area 0
> !
> router bgp 1
> bgp log-neighbor-changes
> network 5.0.0.0
> network 6.0.0.0
> network 7.0.0.0
> network 8.0.0.0
> network 9.0.0.0
> network 10.0.0.0
> !
> ip classless
> ip route 5.0.0.0 255.0.0.0 Null0
> ip route 6.0.0.0 255.0.0.0 Null0
> ip route 7.0.0.0 255.0.0.0 Null0
> ip route 8.0.0.0 255.0.0.0 Null0
> ip route 9.0.0.0 255.0.0.0 Null0
> ip route 10.0.0.0 255.0.0.0 FastEthernet0
>
> Router B :
> --------------
>
> router ospf 1
> log-adjacency-changes
> network 1.0.0.0 0.255.255.255 area 0
>
>
> On the router A, I can see that type 5 LSA is installed for 0/0 and
> propagated to neighbor :
>
> CustomerA#sh ip ospf database
>
> OSPF Router with ID (192.168.254.254) (Process ID 1)
>
>
> Router Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 192.168.108.4 192.168.108.4 592 0x80000003 0x6121 2
> 192.168.254.254 192.168.254.254 592 0x80000006 0x7C72 2
>
> Type-5 AS External Link States
>
> Link ID ADV Router Age Seq# Checksum Tag
> 0.0.0.0 192.168.254.254 4 0x80000001 0x2A22 0
>
> But after some seconds, the external LSA is aged out and so disappears (by
> what ????) :
>
> CustomerA#sh ip ospf database
>
> OSPF Router with ID (192.168.254.254) (Process ID 1)
>
>
> Router Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 192.168.108.4 192.168.108.4 593 0x80000003 0x6121 2
> 192.168.254.254 192.168.254.254 593 0x80000006 0x7C72 2
>
> Type-5 AS External Link States
>
> Link ID ADV Router Age Seq# Checksum Tag
> 0.0.0.0 192.168.254.254 3600 0x80000002 0x301B 1
>
> CustomerA#sh ip ospf database
>
> OSPF Router with ID (192.168.254.254) (Process ID 1)
>
>
> Router Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 192.168.108.4 192.168.108.4 597 0x80000003 0x6121 2
> 192.168.254.254 192.168.254.254 596 0x80000006 0x7C72 2
>
>
> If I use another summary-address (like 4.0.0.0/6 or 8.0.0.0/5), it works
> fine (external LSAs are not aged out).
>
> Why this use doesn't work ? What happens ? Why the LSA is aged out ?
> The purpose of this test was to conditionnaly advertise default routes (if
> BGP routes disappears, default route disappears).
>
> NB : router A is 1750 router with IOS 12.1(14)
>
> Thanks for help,
>
>
> --
> Stephane LITKOWSKI
> Student in a French computer science school
> EPITA Telecom & Network specialization
> CCNA + CCNP
> EMail : [EMAIL PROTECTED]
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=49471&t=49471
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