Link State Routing Protocol Question

"In LSP, one router in each area is designated as the authoritative source of routing information (called a designated router). Each area router receives updates from the designated router" Why need designated router? How it work? Why can?t it just broadcast LSP and leant the routing information without the need of designated router? Is designate router the same as backbone or root area in OSPF? Is "area" concept only be used in Link State Routing Protocol OSPF?

hi...
you will find area topology in IS IS also...
here we are using the Area as well as DR and BDR for reducing the LSA flooding in the area... each router in ospf area will send update to the DR on multicast address and then DR will send the multicast update to all other router in the area... here each and every router in the area have the full adjucancy with DR but they are not in the full adjucancy with any other router ...
hope this will help you
rate this post if it helps
regards
Devang

Similar Messages

Full routing table exchange in Link State Routing?

In link state routing protocols, full update that happen every 30 minutes, does the routers exchange the whole routing table with each other? Or exchange something else, not full routing table. If not the whole routing table, what they are exchanged?

The interval depends on the routing table. OSPF will send out a fresh copy of the LSA (link-state advertisement) every 30 minutes. ISIS will send it every 20 minutes. Only LSAs are sent, not the routing table.
Paresh

LSAs in link state protocols

Lets say we have a stable network and we are using a link-state routing protocol. Then something fails. Will the routers reflood ALL LSAs when one LSA changes or only refloods the changed LSAs?

Francisco
Only the LSA's that have changed will be advetised out. That is one of the big advantages of OSPF in that only affected links are advertised rather than the entire OSPF database.
Jon

Routing loop avoidance in Link State

"The link state method is not susceptible to routing loops which is an advantage over the distance vector method" Why? How it avoid routing loop?

Link-state protocols like OSPF use reliable flooding mechanisms to ensure that all routers are acting on the basis of the same information. Loops occur when routers act on the basis of inaccurate or old information. That is what link-state protocols avoid. All routers in a link-state database have the same view of the network.
Paresh

Link-state protocol on blade switches

Hi,
Can anyone confirm is after an uplink is reestablished the down stream interfaces are automatically restored when using link-state protocol?
The documentation states the downstream ports in a group are put in error disable state but doesn't say if they are automatcally made up when the upstream interface comes back up. This refers to Cisco blade 3020 switches running 12.2.25
http://www.cisco.com/c/en/us/td/docs/switches/blades/3020/software/release/12-2_55_se/configuration/guide/3020_scg/swethchl.html#wp1346176
Thanks
Ken

Link state tracking, also known as trunk failover, provides Layer 2 redundancy in the network when used in conjunction with server network interface card (NIC) adapter teaming. Link-state tracking is used to mirror the state of the ports that carry upstream traffic from connected hosts and servers, and to allow the failover of the server traffic to an operational link on another Cisco Ethernet switch. Check out the following link for more information on link state tracking :
http://www.cisco.com/en/US/products/ps6406/products_configuration_guide_chapter09186a00805a75e0.html#wp1285238
Hope this helps.

Dynamic Routing Protocols - what do I really need to know?

Ok, ridiculously broad question I know but....what I'm trying to figure out is, let's say I'm in a large coproration and I have multiple field sites in different areas of the country so the network setup may be somewhat complex but when it comes to setting up the dynamic routing...is it as simple as let's say, configuring a router to use BGP for whatever portion you designate then just letting it be? is it somewhat challenging to initally configure dynamic routing protocols (i.e. how often have you found yourselves worrying about admin distance, areas (I don't even know what an "area" is yet either so if anyone could explain that I would appreciate it), etc..
So in short, are dynamic routing protocols "Set it and forget it" or do they require a ton of planning to setup? I'm familliar with the differences between them (i.e. OSPF, RIP, EIGRP,etc..) and the differences in link state and distance vector but I just wanted to ask about the setup of the protocols themselves.
Thanks!!

You can exchange routes between protocols with redistribution.
The problem with the question is, as you say, it is too broad to really answer properly.
All routing protocols have different considerations so what you might do for EIGRP you may not do with OSPF and BGP is different altogether.
As a general answer if you are enabling it across a WAN all take a certain amout of planning and design and they all rely heavily on what you have done with your IP addressing in terms of summarisation etc.
The actual configurations to get a basic setup running are relatively simple, certainly for IGPs, but as your network grows you may find the configurations becoming more complex
BGP is a very different in that there are many different commands you can use to influence the path traffic takes but even here to setup a very basic BGP peering only requires a few commands.
But no routing protocol in a large environment should just be configured with no thought as to how it is going to work, traffic paths, number of routes etc.
You can do it but you may well find as your network grows you will end up having to revisit the whole thing because it is not working as you intended.
Like I say it's too large a question to really answer because each routing protocol is different and may or may not meet the requirements of the network.
If there are more specific questions then please feel free to ask.
Jon

DMVPN Routing Protocols

Hi all, I have a couple of questions about routing protocols over DMVPN.
I'm a bit rusty so I'd appreciate if there's mistakes in my understanding if you could correct me.
I understand the EIGRP doesn't ordinarily use the next hop field, receiving routers insert the source of the EIGRP update as the next hop. It uses split horizoning and feasibility tests to detect loops. Over DMVPN you can use the no ip next hop self eigrp command to force eigrp to insert the originating router as the next hop.
OSPF you can specify different OSPF network types - I cannot remember exactly but it may be broadcast networks or multi-access that don't change the next hop?
RIPv2 - I do not understand how RIPv2 works with DMVPN (although I know it does) as to my knowledge Ripv2 does indeed change the next hop.
Can anyone explain how Ripv2 integrates with DMVPN and confirm or correct my understanding of EIGRP/OSPF?
Thanks very much

You're correct on EIGRP. OSPF preserves the next hop of the originating router in all modes except point-to-multipoint. RIPv2 always preserves the original next-hop and this can't be turned off... so it works with DMVPN with no modification except for the split-horizon considerations.
For scaling DMVPN, your worst choice is OSPF because of the large link-state database that forms with so many routers on a single subnet. EIGRP and RIPv2 are very good for DMVPN because the updates are small and simple. These days, I'm moving to BGP for just about all of my DMVPN work... mostly because it scales better than any IGP.

Can i run routing protocol with only F2 line card?

Hello. : )
One question.
Can i run routing protocol such as ospf, bgp, eigrp with only F2 modules? (no M linecard)
Thank you in advance : )

Hi,
Yes, you can use OSPF, EIGRP, IS-IS, etc...
see link below for more info:
http://www.cisco.com/c/dam/en/us/products/collateral/switches/nexus-7000-series-switches/at_a_glance_c45-689339.pdf
HTH

Problems with running EIGRP as PE-CE routing protocol 2

Dear all,
I am facing with the exact problem as a previous user of running EIGRP as the PE-CE routing protocol for a MPLS VPN customer, but in different hardware. The PE router is a 7609-S RSP720-3CXL-GE running IOS 12.2(33)SRC3.
(When I have 33 prefixes or more in the VRF table on the PE, and I try to advertise this network to the CE router (by redistributing BGP into EIGRP), the EIGRP process begins to flap.
I can't advertise prefix more that 32 subnets at a time why?????
The very weird part here, is that when I do debug ip eigrp on the PE and the CE, I can see that the PE router is sending the routes to the CE, but on the CE I can see nothing.)
In my case there is 16 prefixes. When redistributing BGP into EIGRP on allready adjasent EIGRP neighbors everything works perfect, until some side clears it then it begans flaping. On PE router debug is show "retry limit exceeded" ,on CE "Interface Goodbye received"
If solution will be same what software should I use?
Thanks,
George Shiukashvili

George,
Let me ask a few questions:
What is the link layer technology that interconnects the PE and CE that are currently experiencing these issues?
Are there any devices inside the PE-CE path that could at least possibly (and randomly) block multicasts and/or large packets?
Is it possible to modify the EIGRP configuration both on PE and CE to manual neighbor definition using the neighbor commands? This would force all EIGRP comunication between the PE and CE to run as unicast, possibly avoiding some issues with multicast packet delivery.
Is it possible for you to post some show commands from both the PE and CE? I would be interested in seeing the show ip interface, show interfaces, show running-config interface regarding the particular interfaces on PE and CE that connect to each other, and also, I would like to see the EIGRP configuration on both devices.
I agree with the assessment of Mahesh - the preliminary information we have suggest that either the PE packets are not arriving at the CE, or the ACK packets from CE are not arriving back at the PE. Your own debug analysis furthermore revealed that there are no EIGRP Update packets arriving from the PE at the CE. Problems with MTU could indeed cause these problems but it is necessary to inspect the entire path between PE and CE.
Best regards,
Peter

CE dial-in to PE. What routing protocol I should use ?

Hi,
Situation - CE connected to PE via some ethernet interface (primary) and ISDN dial-up as backup, so I need to use some dynamic routing protocol to distribute customers networks to other sites. Now I'm looking towards extended (triggered) RIP, but maybe there are better choices?
As I know, only triggereg RIP and OSPF supports 'on-demand' circuits, but OSPF isn't recommended as CE-PE protocol because it has no VRF awareness and we would have to run separate OSPF process for every VRF what isn't nice. This makes RIP only choice? Or there are another possibilities, maybe BGP ?

Hi,
over all there is static, RIPv2, EIGRP, OSPF, ISIS and BGP for PE-CE.
Well floating static alone seems no possibility in your case.
RIP and EIGRP have some issues when running on redundant links into the VPN (possibility of routing loops), which would be the case with backup active and primary coming back. Depending on the exact topology there might or might not be a workaround.
OSPF has to be run as separate processes. Might be tough on PE resources, depending on your exact setup details. Other than that it does the job.
eBGP with ebgp-multihop and static routes is an option. So eBGP doesn´t go down, just is directed over backup link in case primary is down.
Pick your poison! :-)
regards
Martin

How to restore visited link state to unvisited

Hi all -
I have a pseudoclass which nicely shows a gray background
after being
visited.
After clicking in ie6 browser, the links remain gray forever!
I am unable to view in the pre-visited state to show a client
sitting next
to me.
I am viewing on my local machine
There are no cookies being set
Flushing cache doesn't do it
Closing browser doesn't do it
Even rebooting the machine doesn't do it
I guess my question is, "where is my WinXP machine
remembering the visited
state?"
Anybody know this one? Many thanks
CSS follows
a.inactive
{border: 1px solid #000000;color: #000000;text-decoration:
none;padding: 4px
7px
a.inactive:visited
{border-color: #000000; text-decoration: none;background:
#CCCCCC; color:
#000
a.inactive:hover
{border-color: #000000; text-decoration: none;background:
#B30000; color:
#fff

A: How to restore visited link state to unvisited

Michael
Many thanks for the browser information and for polishing the
CSS
It is indeed appreciated.
"Michael Fesser" <[email protected]> wrote in message
news:[email protected]..
> .oO(Ken Binney)
>
>>I have a pseudoclass which nicely shows a gray
background after being
>>visited.
>>After clicking in ie6 browser, the links remain gray
forever!
>>I am unable to view in the pre-visited state to show
a client sitting next
>>to me.
>>
>>I am viewing on my local machine
>>There are no cookies being set
>>Flushing cache doesn't do it
>>Closing browser doesn't do it
>>Even rebooting the machine doesn't do it
>
> Clear the browser history.
>
>>I guess my question is, "where is my WinXP machine
remembering the visited
>>state?"
>>Anybody know this one? Many thanks
>>
>>CSS follows
>>
>>a.inactive
>>{border: 1px solid #000000;color:
#000000;text-decoration: none;padding:
>>4px
>>7px
>>}
>>a.inactive:visited
>>{border-color: #000000; text-decoration:
none;background: #CCCCCC; color:
>>#000
>>}
>>a.inactive:hover
>>{border-color: #000000; text-decoration:
none;background: #B30000; color:
>>#fff
>>}
>
> A bit shorter:
>
> a.inactive {border: 1px solid #000; color: #000;
text-decoration: none;
> padding: 4px 7px}
> a.inactive:visited {background: #CCC}
> a.inactive:hover {background: #B30000; color: #FFF}
>
> should do the same.
>
> Micha

Does wccp redirect break routing protocol?

This may be a dumb question to ask, sorry i don't have equipment to test it at this moment.
If wccp redirect is configured on an interface running routing protocol (such as eigrp or ospf), will this redirect the "unicast" ospf database or eigrp topology update to WAAS? and/or will this also redirect ospf & eigrp "multicast" update which maintains neighbor relationship to WAAS?
Should this type of traffic be denied on wccp redirect-list?
Thanks

Hi Joe,
Since WAAS normally uses TCP promiscuous mode services, based on service group number 61 and 62 - you'll only get TCP redirected ... and neither OSPF nor EIGRP runs on top of TCP, so don't worry.
If you run a TCP based routing protocol like BGP, it will get redirected.
Later versions of WAAS don't, by default, try to optimize on BGP, as it has given some problems in the past due to sequence number manipulation.
Best Regards
Finn Poulsen

IPSEC tunnel and Routing protocols Support

Hi Everyone,
I read IPSEC does not support Routing Protocols with Site to Site VPN as they both are Layer4.
Does it mean that If Site A has to reach Site B over WAN link we should use Static IP on Site A and Site B Router?
In my home Lab i config Site to Site IPSES VPN and they are working fine using OSPF does this mean that IPSEC supports Routing Protocol?
IF someone can explain me this please?
OSPF config A side
router ospf 1
router-id 3.4.4.4
log-adjacency-changes
area 10 virtual-link 10.4.4.1
passive-interface Vlan10
passive-interface Vlan20
network 3.4.4.4 0.0.0.0 area 0
network 192.168.4.0 0.0.0.255 area 10
network 192.168.5.0 0.0.0.255 area 0
network 192.168.10.0 0.0.0.255 area 0
network 192.168.20.0 0.0.0.255 area 0
network 192.168.30.0 0.0.0.255 area 0
network 192.168.98.0 0.0.0.255 area 0
network 192.168.99.0 0.0.0.255 area 0
3550SMIA#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is 192.168.5.3 to network 0.0.0.0
O    192.168.12.0/24 [110/13] via 192.168.5.3, 3d17h, FastEthernet0/11
     100.0.0.0/32 is subnetted, 1 subnets
O       100.100.100.100 [110/3] via 192.168.5.3, 3d17h, FastEthernet0/11
     3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O       3.3.3.3/32 [110/2] via 192.168.5.3, 3d17h, FastEthernet0/11
C       3.4.4.0/24 is directly connected, Loopback0
C    192.168.30.0/24 is directly connected, Vlan30
     64.0.0.0/32 is subnetted, 1 subnets
O E2    64.59.135.150 [110/300] via 192.168.5.3, 1d09h, FastEthernet0/11
     4.0.0.0/32 is subnetted, 1 subnets
O       4.4.4.4 [110/2] via 192.168.5.3, 3d17h, FastEthernet0/11
C    192.168.10.0/24 is directly connected, Vlan10
     172.31.0.0/24 is subnetted, 4 subnets
O E2    172.31.3.0 [110/300] via 192.168.5.3, 3d17h, FastEthernet0/11
O E2    172.31.2.0 [110/300] via 192.168.5.3, 3d17h, FastEthernet0/11
O E2    172.31.1.0 [110/300] via 192.168.5.3, 3d17h, FastEthernet0/11
O E2    172.31.0.0 [110/300] via 192.168.5.3, 3d17h, FastEthernet0/11
O    192.168.11.0/24 [110/3] via 192.168.5.3, 3d17h, FastEthernet0/11
O    192.168.98.0/24 [110/2] via 192.168.99.1, 3d17h, FastEthernet0/8
C    192.168.99.0/24 is directly connected, FastEthernet0/8
C    192.168.20.0/24 is directly connected, Vlan20
     192.168.5.0/31 is subnetted, 1 subnets
C       192.168.5.2 is directly connected, FastEthernet0/11
C    10.0.0.0/8 is directly connected, Tunnel0
     192.168.6.0/31 is subnetted, 1 subnets
O       192.168.6.2 [110/2] via 192.168.5.3, 3d17h, FastEthernet0/11
O    192.168.1.0/24 [110/13] via 192.168.5.3, 3d17h, FastEthernet0/11
O*E2 0.0.0.0/0 [110/1] via 192.168.5.3, 1d09h, FastEthernet0/11
B Side Config
Side A
router ospf 1
log-adjacency-changes
network 192.168.97.0 0.0.0.255 area 0
network 192.168.98.0 0.0.0.255 area 0
network 192.168.99.0 0.0.0.255 area 0
1811w# sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is 192.168.99.2 to network 0.0.0.0
O    192.168.12.0/24 [110/14] via 192.168.99.2, 3d17h, FastEthernet0
     100.0.0.0/32 is subnetted, 1 subnets
O       100.100.100.100 [110/4] via 192.168.99.2, 3d17h, FastEthernet0
     3.0.0.0/32 is subnetted, 2 subnets
O       3.3.3.3 [110/3] via 192.168.99.2, 3d17h, FastEthernet0
O       3.4.4.4 [110/2] via 192.168.99.2, 3d17h, FastEthernet0
O    192.168.30.0/24 [110/2] via 192.168.99.2, 3d17h, FastEthernet0
     64.0.0.0/32 is subnetted, 1 subnets
O E2    64.59.135.150 [110/300] via 192.168.99.2, 1d09h, FastEthernet0
     4.0.0.0/32 is subnetted, 1 subnets
O       4.4.4.4 [110/3] via 192.168.99.2, 3d17h, FastEthernet0
O    192.168.10.0/24 [110/2] via 192.168.99.2, 3d17h, FastEthernet0
     172.31.0.0/24 is subnetted, 4 subnets
O E2    172.31.3.0 [110/300] via 192.168.99.2, 3d17h, FastEthernet0
O E2    172.31.2.0 [110/300] via 192.168.99.2, 3d17h, FastEthernet0
O E2    172.31.1.0 [110/300] via 192.168.99.2, 3d17h, FastEthernet0
O E2    172.31.0.0 [110/300] via 192.168.99.2, 3d17h, FastEthernet0
O    192.168.11.0/24 [110/4] via 192.168.99.2, 3d17h, FastEthernet0
C    192.168.98.0/24 is directly connected, BVI98
C    192.168.99.0/24 is directly connected, FastEthernet0
O    192.168.20.0/24 [110/2] via 192.168.99.2, 3d17h, FastEthernet0
     192.168.5.0/31 is subnetted, 1 subnets
O       192.168.5.2 [110/2] via 192.168.99.2, 3d17h, FastEthernet0
     192.168.6.0/31 is subnetted, 1 subnets
O       192.168.6.2 [110/3] via 192.168.99.2, 3d17h, FastEthernet0
O    192.168.1.0/24 [110/14] via 192.168.99.2, 3d17h, FastEthernet0
O*E2 0.0.0.0/0 [110/1] via 192.168.99.2, 1d09h, FastEthernet0
Thanks
Mahesh

Hello,
I'm saying crypto maps have a lot of limitations. Tunnel Protection make way more sense
U can configure in 2 ways [ and multicast WILL work over it]
1- GRE over IPSEC
crypto ipsec transform-set aes esp-aes 256 esp-sha-hmac
mode transport
crypto ipsec profile tp
set transform-set aes
int tu1
ip address 255.255.255.252
tunnel source
tunnel destination
tunne protection ipsec profile tp
We have configured mode transport because we encrypt GRE + what ever we encapsule in GRE [ eg OSPF - telnet - http ]
Pros:
We can as well transport IPV6 or CDP
Cons:
4 bytes of overhead due to GRE
2- IP over IPSEC
crypto ipsec transform-set aes esp-aes 256 esp-sha-hmac
mode tunnel
crypto ipsec profile tp
set transform-set aes
int tu1
ip address 255.255.255.252
tunnel source
tunnel destination
tunnel mode ipsec ipv4
tunne protection ipsec profile tp
This config is in fact closer from a crypto map [ from encapsulation standpoint]. The transform-set then NEED to be in tunnel-mode
Pro:
4 bytes overhead less than GRE over IPSEC
Cons:
Cannot transport CDP or MPLS or IPV6. Very limiting IMHO
Cheers
Olivier

LACP or Link State Tracking over VPLS?

Hi all!
I have 2 sites connected with VPLS. Both sites are now having a 2nd VPLS circuit installed (with a different carrier) for redundancy/failover. I've got a Catalyst 3750 at each end to work with.
My question: what's the best way to configure the 3750's? I was thinking either LACP with 2 physical interfaces (one for each VPLS line) - in which case traffic would be balanced across them, which is fine.
OR I could use Link State Tracking, such that if 1 link fails it would failover. Though I'm new to Link State Tracking so I don't know if this would actually work over VPLS.
Your thoughts are very appreciated.

Link state tracking, also known as trunk failover, provides Layer 2 redundancy in the network when used in conjunction with server network interface card (NIC) adapter teaming. Link-state tracking is used to mirror the state of the ports that carry upstream traffic from connected hosts and servers, and to allow the failover of the server traffic to an operational link on another Cisco Ethernet switch. Check out the following link for more information on link state tracking :
http://www.cisco.com/en/US/products/ps6406/products_configuration_guide_chapter09186a00805a75e0.html#wp1285238
Hope this helps.

Link-state tracking on 3550

Hi,
I would like to know if the link-state tracking is supported on the 3550. If yes then please let me know on which IOS version. I was not able to check this on the IOS features.
Second question:
Can I trak on sub-interface (VLAN) instead of the full interface?

Hi Amin
I checked out for the same and it says its supported in Cisco 3550 but regarding the exact ios code you better can choose the required version from the feature navigator.
http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp
regds

Link State Routing Protocol Question

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