12-03-2024 04:37 AM
Hi, I have a question. If there is a DR, then LSA type 2 will be sent to all other routers, but why is DROTHER also sending individual LSA Type 1? I understand LSA Type 2 a little bit, which is that it is used to obtain the information of the router presented in the same subnet and multicast network.
12-03-2024 04:48 AM
If you check opsf db you will see advertiser router IP' without lsa1 this IP is unknown for other router
MHM
12-03-2024 05:07 AM
CAN YOU EXPLAIN ME LSA TYPE 2 FROM SCRACTH BECAUSE I AM NOT ABLE TO UNDERSTAND THIS CONCEPT
12-03-2024 05:22 AM - edited 12-03-2024 06:14 AM
Router# show ip ospf database asbr-summary
OSPF Router with id(192.168.239.66) (Process ID 300)
Displaying Summary ASB Link States(Area 0.0.0.0)
LS age: 1463
Options: (No TOS-capability)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 172.16.245.1 (AS Boundary Router address)
Advertising Router: 172.16.241.5 <<- this IP
LS Seq Number: 80000072
Checksum: 0x3548
Length: 28
Network Mask: 0.0.0.0 TOS: 0 Metric: 1
This example of show ospf db' do for all type of lsa and you will see advertiser router IP. This IP is learn from LSA1.
MHM
12-03-2024 05:59 AM
Hello
@MHM Cisco World wrote:
Router# show ip ospf database asbr-summary
This is incorrect what you are showing there is a type-4 LSA, the command for type 2 LSA is:
sh ip ospf database network
12-03-2024 06:14 AM
Apologies
Again you need to refresh your acknowledge.
MHM
12-03-2024 06:58 AM
Hello
@MHM Cisco World wrote:
Again you need to refresh your acknowledge.
If your suggesting that your previous example of type4 lsa is related with a type 2 then you are mistaken
What you are showing is a external type LSA 4 originated from some ABR rtr advertising a destination of an ASBR located on a rtr in one of those areas.
The OP is querying type 2 LSAs and their functionality in OSPF it has nothing to do with type 4 LSAs and their functionality
So can you explain or any other please what i need to update my knowledge of as would be happy to say i am wrong if that is the case - as in essence that is what these forums are all about?
12-03-2024 07:30 AM - edited 12-03-2024 08:33 AM
Friend I really want to answer you but I have alot of topic need to cover
regarding LSA4 if Router send LSA4 to all routers to use this IP, how other routers know this IP ?
this job of LSA1
each routers advertise LSA1 to declare to all other routers these IP belong to me.
these IP can use for forward address for LSA4 and for other.
sorry again, if I am not answer you you can send me PM
MHM
12-03-2024 08:29 AM - edited 12-03-2024 08:35 AM
Hello @MHM Cisco World
i will stipulate this again - a type4 has absolutely nothing to do with a type 2 and i’ve no idea what ypu are talking about in reference to the OP what happens iif there is no muticaess network as such no DR so no type 2 what then?
So apologies I believe your understanding is incorrect not mine however this is open to discussion to the wider audience and i’m happy to be corrected
Edited
in addition you still haven’t explain g why would you show a command for a type 4 lsa when the command for a type 2 lsa exists ?
12-03-2024 05:16 AM
Hello
@MHM Cisco World wrote:
If you check opsf db you will see advertiser router IP' without lsa1 this IP is unknown for other router
Can you elaborate please , not sure what you mean "IP is unknown" ?
12-03-2024 05:13 AM - edited 12-03-2024 05:14 AM
Hello
@surendrasinghtanwar667 wrote:
Hi, I have a question. If there is a DR, then LSA type 2 will be sent to all other routers, but why is DROTHER also sending individual LSA Type 1? I understand LSA Type 2 a little bit, which is that it is used to obtain the information of the router presented in the same subnet and multicast network.
If you have DR/BDR then you have a multi access network segment, as such Type 2 LSAs advertise this and It the Drs responsibility to flood these type 2 lsas to all others rrtr on this same segment including rtrs that are DRothers.
Ospf Drothers are also rtrs obviously... and they send their own list on routed links via type 1 LSAs (router LSAs) just like another ospf rtr would do
12-03-2024 05:30 AM
SO TYPE 1 LSA IS ONLY SENDED TO DR ONLY
12-03-2024 06:10 AM - edited 12-03-2024 06:11 AM
Hello
Correct to the all DR routers mc address 224.0.0.6., in turn ONLY the DR will flood it updates to the all ospf routers on 224.0.0.5 mc address
12-03-2024 06:03 AM
Suppose that there are 5 Router. R1 R2 R3 R4 R5 R6 they are in multi access network and R1 AND R2 are DR AND BDR. There is one more router R6 which is not the part of this multi network access which is directly connected to R1 via serial cable so my doubt is either all DROTHER will send their individual LSA TO R6 or all DROTHER Router will send LSA to DR Router and then DR Router will send LSA 2 to R6 for creating complete topology of the entire network. Just clear this question
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12-03-2024 08:49 AM - edited 12-03-2024 09:10 AM
Hello
so if you have an additional rtr that is directly connected via serial as such then no DR/ DR will it exit between RTR1 and RTR6 - you see a rtr can have various ospf network types running at the same time so even though rtr 1 is DR on one interface it can be a BDR/DRother or just a P2P on another -
as such in your example the the ospf link type will no doubt become a P2P so no type 2 lsas will exist - the rtr wi just exchange lsa type1/2 unless either rtr is also an abr/asbr etc..
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