MPLS/OSPF Fasthellos

I am setting up an MPLS VPN network.
Customer needs fast convergenace.
So I thought backbone IGP(OSPF) could be configured with fast hellos for the same. At the time of a backbone link failure, even if OSPF converges fast customer is experiencing an outage of 20 seconds between the CPEs(normal ping). I think the longer switchover delay may be due to LDP convergence. Can someone help me with this.
Any idea of reducing LDP convergence time.
I am using 4948 switches.
Thanks in advance
AneesH

Hello Anish,
Greetings of the day,
Well MPLS VPN Convergence Times Depending on the PE-CE Protocol. We have different protocols having the following convergence time as below:
Static: 25 seconds
OSPF: 35 seconds
BGP: 85 seconds
EIGRP:25 Seconds
RIPV2 :85 seconds
Option 1:
You can use static routing in between PE-CE as there is a 60 sec convergence difference between static and BGP routing protocols.
Option 2:
Tuning the BGP
The main delay in route convergence with the BGP protocol is the time taken to advertise a new or deleted VPN route. This time is primarily driven by the advertisement interval timer. This is set by default to 5 seconds for internal BGP (convergence point T4) and 30 seconds for external BGP (convergence points T1 and T7).
you can chose to reduce the internal BGP timer to 1 second and the external BGP timer to 5 seconds. These new timer values allow routes to be distributed across the backbone network more quickly. They also provide a small delay for the advertisement of these routes to external peers to allow a certain amount of packing of routes into the updates.
Using these new timer values, you can able to drop the theoretical maximum convergence time (when BGP-4 is used on the PE-CE links) to 27 seconds. (This is the default theoretical maximum of 85 seconds minus twice a 4-second saving for internal BGP and twice a 25-second saving for external BGP.) This time is more inline with the other routing protocols.
Option 3:
hello state timer:RSVP hellos can be used to detect when a neighboring node is down. The hello state timer then triggers a state timeout. As a result, network convergence time is reduced, and nodes can forward traffic on alternate paths or assist in stateful switchover (SSO) operation.
Or you can use BFD for link failure between PE and CE
Cheers!!!
Inderdeep

Similar Messages

Help me on MPLS/OSPF very urgent

I have configured OSPF in my network into 2 areas (backbone & area 1) for supporting
MPLS. Now i have somes problems with it.
1. I verify OSPF on the R1
R1#sh ip route x.x.y.1
Routing entry for x.x.y.1/32
Known via "ospf 1", distance 110, metric 2, type intra area
Last update from x.x.y.129 on GigabitEthernet1/48, 00:10:52 ago
Routing Descriptor Blocks:
* x.x.y.129, from x.x.y.1, 00:10:52 ago, via GigabitEthernet1/48
Route metric is 2, traffic share count is 1
And the time 00:10:52 ago is the same on the others routers (ALL ROUTERS R2,R3,R4 ..)
and for any subnets int the network OSPF (X.X.X.X/Y)
and then after a few minutes
R1#sh ip route x.x.y.1
Routing entry for x.x.y.1/32
Known via "ospf 1", distance 110, metric 2, type intra area
Last update from x.x.y.129 on GigabitEthernet1/48, 00:10:52 ago
Routing Descriptor Blocks:
* x.x.y.129, from x.x.y.1, 00:00:12 ago, via GigabitEthernet1/48
Route metric is 2, traffic share count is 1
And the time 00:00:12 ago is the same on the others routers (ALL ROUTERS R2,R3,R4 ..)
and for any subnets int the network OSPF (a.b.c.d/e)
Sometimse i found that the period is 10 minutes, 15 minutes and
it's a variable value.
Please tell me why and how to fix it.
Thanks so much

Hi,
I think LSA refresh time might have caused this timer to change in OSPF database. Routers originating the LSA send a copy again to refresh the old entry..
If the timer in routing table shows decrement , it means there was withdrawl of route at some point of time and it has been reinserted in Routing table..
regards,
Gaurav Prakash

MPLS + OSPF default rote weird problem (cat6509)

I have two cat6509.
Switch A is connected to the internet and receive an OSPF default-route.
Switch A an B is connect trough a MPLS Tunnel with traffic eng..
When I setup an notebook connected to the Switch B I canno't reach the internet. But If I change in the switch B the default-route learned trough ospf to static one pointing to the lo0 of SwA it works fine.
And another thing weird.
If I let the original config, SwB learning the default-route via Tunnel171 OSPF, I can reach the internet from the notebook If I change the SwB to process switch the packets.
Someone can help?

Hi,
this sounds somewhat wierd, I agree. Did you configure "mpls ip default-route" on both 6509? This allows for label switching of the default route.
It would lso be interesting to get an output from "show mpls ldp discovery", "show mpls forward" and "show ip cef 0.0.0.0 detail" in both cases default through ospf or through static (in case there are any differences).
Regards, Martin

MPLS OSPF Problem

Hi,
Anyone know the cause of the problem below ? This log appeared after ospf establish.
%OCE-SP-3-UNEXPECTED_SW_OBJ_TYPE: SW_OBJ handle/type mismatch; expecting oce type label, found 1
Thanks,
Gilang.

Hi
This seems to be a bug. Please check the below URL and search for SW_OBJ handle/type mismatch
http://www.cisco.com/en/US/docs/ios/system/messages/guide/sm_cn07.html
regards
shivlu jain
http://www.mplsvpn.info

L2-MPLS-IOS Support

Hi all,
need help. we r ISP and we need to implement L2-MPLS, we hv 7513 in our network as a PE and need to know which IOS will support L2-MPLS,QoS,MPLS OSPF,MPLS RIP.
Thanks & Regards,
Ciscobuddy

The following images for 7500 which is of 12.0(26)S release might help you in implementing your requirement "rsp-pv-mz.12.0-26.S1" or "rsp-pv-mz.12.0-26.S". This image requires 128MB of DRAM and 16MB of flash .

OSPF design for branch offices across MPLS

Hello fellow networking engineers,
I want to implement OSPF in our network. We have multiple branch offices, all linked to an MPLS backbone.
I know that in order to get linked areas, I would need to setup GRE tunnels between them, but I want to avoid static/manual configurations as much as possible. With multiple sites, it would become cumbersome to create a mesh real fast.
Is running OSPF independent areas at each site, and simply redistributing over eBGP a valid solution? This will host voice and data, and will failover to VPN connection (Cisco ASAs) if the MPLS goes down.
For the VPN backup links, I thought of two options. Either simply using the default route to send everything to the ASA in case of MPLS "death", or inject routes using IP SLA...
Any input would be appreciated.

Marc
You don't GRE tunnels to link your areas if that is what you want to do.
If the SP supports it then you can exchange your OSPF routes between areas and they will still be seen as inter area routes rather than OSPF externals which they would if you simply treated each area as isolated from each other.
In effect the MPLS network becomes an OSPF super backbone area and your main site would also be part of the backbone area with all your other sites having an area each.
You still redistribute your OSPF routes into BGP but with some extra configuration on both your CEs and the SP PE devices.
Like I say you would need to check with your SP but it is possible.
Whether or not you need or want it I don't know.
Your other option is as you have proposed to treat each OSPF area as an isolated one and simply redistribute into OSPF at each CE. Then within each site all non local routes would be seen as OSPF external routes.
Either way in terms of backup I would keep it simple and use a default route at each site pointing to the ASA device. I can't see what you gain from IP SLA because if the main MPLS link goes down at any site the only other path they have out is via the ASA so there is nothing really worth tracking.
The only other thing I would mention is remote site to remote site traffic. If there is any then presumably with your VPN tunnels you would be doing a sort of hub and spoke where the hub is the main site so you may need to think about traffic coming in from one VPN tunnel and going out to another VPN tunnel on the main site ASA.
This would only really be needed if two or more sites had to use their backup links at the same time.
In terms of which is better ie. OSPF inter area across the MPLS cloud or OSPF externals I can't really say to be honest. With the MPLS networks i have worked on we ran EIGRP and simply treated each remote site as an isolated AS.
If you are already running OSPF then you may want to preserve your existing areas so it would make sense to go with the inter area option.
If it is a new setup then I don't really know the pros and cons of either so can't really comment.
Perhaps others may add to the thread with their thoughts.
Jon

OSPF downward bit in MPLS network

Hi all,
I have an issue with using the OSPF downward bit and hope someone has seen this before. It appears to do nothing in this example to prevent routes being learnt via the wrong path. That is via a backup router that has learnt the route from the site primary router which has received the OSPF route originally redistibuted into OSPF from the PE (with downward bit set).
The docco says:
"The down bit is used between the PE-routers to indicate which routes were inserted into the OSPF topology database from the MPLS VPN super-backbone and thus shall not be redistributed back in the MPLS VPN super-backbone. The PE-router that redistributes the MP-BGP route as OSPF route into the OSPF topology database sets the down bit. Other PE-routers use the down bit to prevent this route from being redistributed back into MP-BGP. "
Therefore I would not expect a route received with the downward bit set to be installed into the route table nor BGP table however the below shows it is? This has essentially created a routing scenario where core routes are learnt via a dual OSPF attached access site.
The PE receiving the incorrect route:
7609#sh ip ospf 116 database summary 192.168.104.0
            OSPF Router with ID (10.200.204.116) (Process ID 116)
        Summary Net Link States (Area 0)
LS age: 1094
Options: (No TOS-capability, DC, Downward)
LS Type: Summary Links(Network)
Link State ID: 192.168.104.0 (summary Network Number)
Advertising Router: 10.200.212.116
LS Seq Number: 80000013
Checksum: 0xFDB1
Length: 28
Network Mask: /24
    MTID: 0     Metric: 1798
7609#sh ip route vrf RED 192.168.104.0
Routing Table: RED
Routing entry for 192.168.104.0/24
Known via "ospf 116", distance 110, metric 1798, type intra area
Redistributing via bgp 100
Advertised by bgp 100 match internal external 1 & 2 nssa-external 1 & 2
Last update from 10.1.59.138 on GigabitEthernet1/0/1.3684, 00:18:23 ago
Routing Descriptor Blocks:
* 10.1.59.138, from 10.200.4.229, 00:18:23 ago, via GigabitEthernet1/0/1.3684
      Route metric is 1798, traffic share count is 1
7609#sh ip bgp vpnv4 vrf RED 192.168.104.0
BGP routing table entry for 100:116:192.168.104.0/24, version 195113
Paths: (1 available, best #1, table RED)
Advertised to update-groups:
     1
Local
10.1.59.138 from 0.0.0.0 (10.200.0.65)
      Origin incomplete, metric 1798, localpref 100, weight 32768, valid, sourced, best
      Extended Community: RT:100:116 OSPF DOMAIN ID:0x0005:0x000000740200
        OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:10.200.204.116:512
      mpls labels in/out 312/nolabel
7609#
Regards,
Kent.

Ive implemented what I consider to be a workaround, but it does now work as expected. I had to filter the updates received by the PE from the primary CPE at each site to only accept the LAN range from that site, not the LAN range from other sites that it was learning via the backup CPE, via PE, via other site backup router. I think I was barking up the wrong tree re the downward bit. This issue is because there is indirect OSPF connectivity between all the CPE's connected to the same PE. Basically the PE needs to never pass on LSA's learnt from one CPE to another CPE then we would be all ok.
I still have an issue to solve for PPP xDSL services as they all share the one loopback as an ip unnumbered interface on the PE. The same distribute list approach wont work there.
Here is what I have done. There must be a less config intense and flexible approach to this.
router ospf 116 vrf RED
distribute-list prefix RED-acacia-ospf-subnets-inbound in GigabitEthernet1/0/1.3681
distribute-list prefix RED-acacia-ospf-subnets-inbound in GigabitEthernet1/0/1.3682
distribute-list prefix RED-geebung-ospf-subnets-inbound in GigabitEthernet1/0/1.3684
distribute-list prefix RED-kawana-ospf-subnets-inbound in GigabitEthernet1/0/1.3685
distribute-list prefix RED-goldcoast-ospf-subnets-inbound in GigabitEthernet1/0/1.3686
ip prefix-list RED-geebung-ospf-subnets-inbound permit 192.168.103.0/24
ip prefix-list RED-acacia-ospf-subnets-inbound permit 192.168.100.0/24
ip prefix-list RED-acacia-ospf-subnets-inbound permit 0.0.0.0/32
ip prefix-list RED-kawana-ospf-subnets-inbound permit 192.168.104.0/24
ip prefix-list RED-goldcoast-ospf-subnets-inbound permit 192.168.101.0/24

OSPF problem in a GSR12000 with MPLS interfaces

Hi,
I am using an MPLS interface connected to other vendor routers.
OSPF is set on the MPLS interface.
The OSPF did not synched with the other vendor OSPF due to the following :
00:45:55: OSPF: Rcv DBD from 10.10.55.113 on GigabitEthernet4/0 seq 0x178476E opt 0x42 flag 0x7 len 32 mtu 1500 state EXSTART
00:45:55: OSPF: First DBD and we are not SLAVE
00:46:00: OSPF: Retransmitting DBD to 10.10.55.113 on GigabitEthernet4/0
00:46:00: OSPF: Up DBD Retransmit cnt to 1 for 10.10.55.113 on GigabitEthernet4/0
00:46:00: OSPF: Send DBD to 10.10.55.113 on GigabitEthernet4/0 seq 0x745 opt 0x52 flag 0x7 len 32
00:46:00: OSPF: Rcv DBD from 10.10.55.113 on GigabitEthernet4/0 seq 0x178476E opt 0x42 flag 0x7 len 32 mtu 1500 state EXSTART
00:46:00: OSPF: First DBD and we are not SLAVE
After diagnosing the problem we found out that if the loopback router-id address value is bigger then the neighbores IP address then you will get this problem.
If you will change the router-id ip address for 1.1.1.1 and the MTU is set ok (to be 1500 on the MPLs i/fs) then it will work well !
Regards,
Simhon Doctori.

Hi,
Sorry for barging in on this. Can you please tell me how this Master/Slave relationship comes into play in conjunction with DR. DR is a focal point for distributing LSD and propagating all the updates on broadcast or NBMA networks.
a. What if DR has a RID of 1.1.1.1 which is lower
than any other RID on a segment?
b. Will it be chosen as Master anyhow?
c. What if a topology change occurs on a Slave
router, it is allowed to update the Master?
Is there the same Master/Slave notion in other routing protocols, specifically ISIS, EIGRP and BGP?
Thank you very much.
David

Why OSPF is not used in MPLS, though it is very efficient protocol

Dear all, though OSPF is a very efficient protocol, with a number of features to handle much larger networks,it is not used in MPLS. Can u plz let me know, what special features BGP posses over OSPF, for its selection in MPLS.

For core MPLS switching, any routing protocol can be used, including static. Service providers have preferred to use link state protocol like OSPF and ISIS and they still do.
However, different MPLS applications have their routing protocol requirements. MPLS Traffic Engineering for example requires a link state protocol. Hence, if you want to do Traffic Engineering, your IGP must be either OSPF or ISIS. This is because for proper operation of MPLS TE, the routers should have a complete topology view of the network, so as to be able to route packet accordingly.
For MPLS VPN, there is a requirement to deploy iBGP on the edge routers. The main requirement stems from label allocation procedure of MPLS. While MPLS routers assigns a label for every route in the FIB, routes learned via BGP are exempted. Rather, for BGP learnt routes, the label for the BGP next-hop of the route is used. This is critical to the operation of the MPLS VPN, because it effectively creates a tunnel and ensures that every router on the network does not have to carry all the VPN routes.
I hope the explanation is clear

OSPF opaque (MPLS-TE)

I have some question:
1.MPLS traffic engineering use opaque (LSA type 9,10,11) to get eg. BW of the link!
But in OSPF , when there is a change in an area, the LSA will flood to all. So if there is an application transfer a file on the link, the BW will change continuosly (?), so the LSA will flood and how can the CR-LDP know what information about BW on that link to use.
2.In an multi-area OSPF network, which router will start the label distribution process??
3.Is there any document about opaque with MPLS-TE. I try RFC3630 but it's very difficult to understand.

Hello,
MPLS TE is a pure control plane feature. So:
A1) The announced bandwidth does only change when there is a new "booking". This means that only when a new tunnel is routed over a link, when a tunnel is removed from a link or when a link up/down event occurs flooding is needed. To control the amount of opaque LSAs, thresholds are used for the booking bandwidth value.
The real bandwidth utilized at any moment in time is not taken into account by MPLS TE!
A2) Every MPLS TE enabled router will send LSA 10 and ABRs will insert this info into other areas. So pretty much LSA generation and flooding does not deviate from "normal" OSPF LSAs.
A3) I would also read "RFC 2370, The OSPF Opaque LSA Option".
Hope this helps! Please rate all posts.
Regards, Martin

MPLS P-to-PE OSPF Inter-Area failover

Hi Guys.
I am simulating a MPLS core using OSPF for the control plane IGP.
Here's the setup:
Area 0 - backbone
Area 1 - PE routers in location A (PE-A)
Area 2 - PE routers in location B (PE-B)
Network is running MPLS/VPN
Here are the requirements:
1. There will be nxGE links between PE-A and PE-B for better latency requirement and bypass Area 0 for Location A<>B destined traffic
     - I can probably use a new direct route between PE-A and PE-B to establish MP-BGP.
2. When Area 1 to Area 0 links are down, Area1 should failover via Area 2.
    And when Area 2 to Area 0 links are down, Area2 should failover via Area 1.
    - I can probably use virtual-links here...But I dont want to complicate things.
Any recommendations on better design?
Thanks

A long time ago the rule of thump was that you can have up to 50 routers in one area. This was at the time that the routers and switches had low CUP speed and memory. Now days, the router and switches are powerful enough that can handle the database of more than 50 routers. I don't think this is going to be an issue with 24 routers, specially since you already have 20 routers in one area.
HTH

Understanding OSPF For MPLS Superbackbone.

LSA1 is Router LSA And LSA2 is Network LSA.What is the difference between them?In which direction are they propogated?I need to understand it neatly as I am studying it for MPLS Superbackbone .

In short, the router LSA is generated by all routers and describe all the connected interfaces on that router.
The network LSA is generated by the Designated Router (DR) only and describe all the routers connected to the broadcast or NBMA network for which this router is the DR.
If you need more information on what the LSA are for and the details of OSPF in general, I would recommend you read RFC2328.
Here's the link for it:
http://www.ietf.org/rfc/rfc2328.txt?number=2328
Hope this helps,

OSPF between Multiple MPLS Service Providers

Hi,
One of my customer currently connects to three different MPLS providers. All the SP's PEs are already configured with the customer's subnets, but the CE is configured to point only to one of the PE as the default route. If the link to this SP is down, the customer need to manually change the default route to point to another SP.
How can I enable dynamic routing, e.g. OSPF, to all the of service providers? What is required from the service providers to enable this?
Thanks for all the advice.
rgds,
Arief

A better understanding of the full topology, such as all the branches that this CE is talking to, and via which of the SPs they are reachable via would help.
I do not see much problem, more especiall, if you take the pains to configure the routing protocol on the CE to only advertise the local subnet and not other subnets learnt by it.

Voice Traffic over MPLS-enabled OSPF running backbone links

Hi All;
We have running frame-mode MPLS backbone and OPSF as well. Voice as real-time traffic is passing through our backbone links and marked with precedence 5 as an ordinary behaviour.
What i face is that i can not balance the voice traffic between the uplinks of the LER routers through LSR routers. Let me summarise like this.
I have a PE that has 4xE1 connection as uplinks terminated at two different LSRs. However, when i look at the voice traffic distribution from PE to Ps,the general attribute is voice traffic is choosing only one E1 and uses it. And other links are not used so much by voice traffic. And this causes poor quality of voice because, it exceeds the amount of the reserved bandtwidth that is defined via LLQ under the backbone links. I have also re-defined the priorty class bantwidth and raised it as much as it can be defined, but now, the business in contract traffic is under danger. :)
As OSPF does not support unequal load-balancing and also "load-sharing per-packet" command sucks the voice traffic, there is nothing to balance the voice traffic on the backbone links.
By the way, i have defined MPLS/TE tunnels that are PE-PE tunnels, according to my observations of voice traffic goes to where. I tried to balance the output traffic somehow but the situation is still the same. Sometimes, traffic chooses one tunnel and goes over there. In fact this problem bears with CEF itself but this is another case.
So any suggestion how i can come over this obstacle. Thanks in advance.
Regards,
Baris.

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
BTW, 20 Mbps can push the practical performance capacity of a 2821.
class-map match-any LLQ
!match your VoIP bearer traffic here
policy-map Shape20M
class class-default
shape average 17000000 !we're shaping 15% slower to allow for L2 overhead
service-policy Sample
policy-map Sample
class LLQ
priority percent 30
class class-default
bandwidth remaining percent 100
fair-queue
interface tunnel #
ip tcp adjust-mss 1436
ip mtu 1476
service-policy output Shape20M
tunnel path-mtu-discovery
keepalive 1

OSPF path MPLS/point to point

Hey Guys,
I have two links on my router;
R1 ----- MPLS -----R2 ------------------------------------------1st link
R1-----pt to pt -----R3------MPLS----R2 ---------------------2nd Link
by default I am using 1st link and I would like to move to 2nd link, can anyone help how do I do that ?

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
From R1 to R2, correct? (R2 to R1 could be tricky - depends on how R2 interact with MPLS).
For R1 to R2, you could just set a direct (high) OSPF interface cost on the R1 port to MPLS.

MPLS/OSPF Fasthellos

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