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Community Member

BGP Multihome/Hesitation

Hello All -

Sorry if I don't explain this correctly, but I'm still learning BGP terms, etc.  The individual that set this up left the company.  First, I'll give a quick rundown of the network and why it's this way.  Then, I'll explain the issue. 

Background -

We have 2 ASR1000's that are handling BGP from 3 different providers.  ASR1 has a Gig-E connection to L3, ASR2 has a Gig-E to Sprint, and OC3 to AT&T.  The Sprint connection was recently converted from OC3 to Gig-E approx 4 weeks ago.  The original Sprint OC3 connection was going through a "route-map poison-route permit 10 & route-map poison-route permit 20 (with prepends on both)".  The Gig-E connection to Sprint was currently being finalized when the L3 connection was severed due to fiber cut.  As a result, we decided to fire up the Sprint Gig-E connection.

Currently, The Sprint GbE connection (ASR2) is not going through any type "route-map poison-route".  Either is the L3 connection (ASR1).  We are running OSPF w/BFD on our core routers and edge devices. 

L3 - Running approx 500 MB

Sprint - Running approx 250 MB

Issue -

It seems since we've fired up both GbE connections to the different providers, our users notice a "hesitation" when pulling up websites or sending traffic.  Once the hesitation has passed, traffic flows normally.  Example, pulling up www.youtube.com, takes a couple of seconds, but once it goes, everything seems fine.  Streaming a Netflix video - initial load takes a while, then no problems

Question(s)  -

Is it possible the problem exists because 2 GbE links on two different ASRs are sharing equal "routing"?

Should I consider sending one of the links to a "route-map poison-route" with AS prepends?

Or, is it possible the issue lies within BFD on my 7609 and 6509 routers?

Thanks for the help and ideas!

Everyone's tags (3)
3 REPLIES

BGP Multihome/Hesitation

Interesting scenrio! Altough there is a lot to tweak here, I find it hard to find a straightforward issue relating to the changes you mentioned.

Delays like this are typically caused by dns related problems.

Did you already try that venue?

regards,

Leo

Community Member

BGP Multihome/Hesitation

Leo,

Funny you ask about DNS.  I was packet capturing after I sent this message.  Noticed that the Standard DNS query launched, but took quite some time to "respond".  I'm working with our DNS guys now to see if they notice anything.

Regards,

Rob

Community Member

BGP Multihome/Hesitation

Definetly DNS issue.

Thanks for the input!

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