Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

BGP Loadsharing

Hi Experts

2 questions Pls

1)I Have the below topology runing BGP with a Public AS along  with a Class C Address obtained from RIPE,i am advertised my addresses Block to Both ISP's,while i receive default-route from both ISPs

the questions is can i have LoadSharing on both links to  ISPs ,because the links are unequal

R1-----------------16Mbps------------------------ISP-1

.

.iBGP

R2-----------------8Mbps-------------------------ISP-2

2)i jave Talkek to both ISP to advertise the /24   to /25 but both refused to advertise the /25

PLs advise on the above questions

thanks

15 REPLIES
Super Bronze

BGP Loadsharing

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

If supported on your platform, OER/PfR can manage dynamic unequal bandwidth load sharing (outbound).

New Member

BGP Loadsharing

Hi Joseph

thanks for ur reply

i was wondering why y add the below when y reply me

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.

-----------------------------------------

we have 2xasr 1006

can y help to acheive that great setup , i would be much appreciated

Super Bronze

BGP Loadsharing

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

Ibrahim Jamil wrote:

Hi Joseph

thanks for ur reply

i was wondering why y add the below when y reply me

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.

That's to mitigate my risk to agreeing to "CISCO SUPPORT COMMUNITY ACCEPTABLE USE AGREEMENT", especially paragraph 11, and is much like their paragraphs 10 (c) and 12.  Unfortunately, I'm unable to get you to only agree one-time.

we have 2xasr 1006

can y help to acheive that great setup , i would be much appreciated

Unfortunately, I haven't yet worked with the ASR 1000 series, so I don't have a suggested template that I know to work on that platform.

Super Bronze

BGP Loadsharing

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

Just came across recent posting that provided: http://docwiki.cisco.com/wiki/PfR:Solutions

Might help you.

BGP Loadsharing

Joe,

you seem to be a big champion of OER/PfR . seen u suggest this in heaps of posts lately

Kishore

Super Bronze

BGP Loadsharing

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

Kishore Chennupati wrote:

Joe,

you seem to be a big champion of OER/PfR . seen u suggest this in heaps of posts lately

Kishore

That's true, but then there seems to be more posts opened on load balancing/sharing too.

The reason I champion this technology, my background is in software development, so I appreciate what computer automation can do to improve certain situations.  Using routing "intelligence" to pick the best performing path(s) appears to be the next logical progression, i.e. static routing => dynamic routing => performance routing.

I'm not using this technology at my current job , but at my prior job I configured OER to support 60 some international sites with dual L3 VPN (MPLS) clouds.  It dealt with some intractable performance issues, like poor performance across part of a MPLS vendors infrastructure, which could be critical supporting things like VoIP.  The biggest initial complaint I got was the network management people no longer "seeing" WAN performance issues - .  Seriously, this was a problem as we did want to know there was a WAN cloud issue, we just didn't want it to impact our actual traffic.  (Solution was two fold, have network management SLA tests not processed by OER and analyze what OER was doing.)

OER/PfR is impressive stuff - there are a couple of "gotchas" you can bump into, and it's still early in its life cycle, so you may want to avoid it if you need 100% predictability. Of course, 100% "traditional" predictability also can mean such-and-such happens and performance and/or the network drops.  A real example, one day one of our MPLS vendors nodal locations started to black hole all traffic, but routing looked fine.  It took hours to manually identify where the problem was and manually re-route to avoid the problem. OER/PfR can detect and route around an issue like this in seconds.

New Member

BGP Loadsharing

Thanks Guys

I Wanna keep this thread open,

BGP Loadsharing

Joe,

Yep, I agree with you as well.  Its the next best thing when it comes to load sharing multihomed environments.

I would be setting up OER/PfR shorlty in our env as we seem to have some WAN performance issues.

Ibrahim,

In regards to your second question. there is no clear cut answer to this. Most SP's filter /25's etc so they dont like to change policies etc to accept longer than /24. Allowing /25's also means more prefixes in the cloud which is not scalable as well. However, your ISP's can accept /25 from you but will advertise /24 to the upstream  so it sort of doesn't help.  Try any of the route-servers at www.traceroute.org  and use "sho ip bgp cidr-only | inc /25" to investigate.

You will see none of the ISP's have prefix with /25's

Do you see what I mean?

HTH

Kishore

New Member

BGP Loadsharing

Hi Kishore

I Receive from both ISPs a default route so the question

thanks

BGP Loadsharing

Hi Ibrahim,

You can achieve this by configuring the BGP multipath.

BGP Multipath allows installation into the IP routing table of multiple BGP paths to the same destination. These paths are installed in the table together with the best path for load sharing.

These are the BGP Multipath features:

eBGP Multipath—maximum-paths n

iBGP Multipath—maximum-paths ibgp n

eiBGP Multipath—maximum-paths eibgp n

n<=6

In your case you should have eBGP with the ISP peers and to activate the parallel paths, you need to enable eBGP multipath

R5(config)#router bgp x
R5(config-router)#maximum-paths 2

Hope that helps!

Vasilis

BGP Loadsharing

Vasillis/Ibrahim,

When using  "max-paths" in BGP there are some considerations to look into.

Please read the below link.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

HTH

Kishore

BGP Loadsharing

Hi,

Yes, I know that max paths in BGP have some requirment to work but in our case (Ibrahim request) seems that maximum path can solve his problem.

He receives two default routes from a direct eBGP neighbor (ISP), so the required BGP attributes  to "max paths" to work and load share the outbound traffic should be ok.

In any case, these attributes can also be modified by Ibrahim router in order to be common for both ISP default bgp routes and max path to work!

New Member

Re: BGP Loadsharing

Hi Kishore , Hi Vasileios

load share the outbound traffic , does it means "TRAFFIC LEAVING UR AS TOWARDS UPSTREAM ISP's"? while the inbound traffic or download means traffic enter ur AS Number???

thanks

Jamil

Re: BGP Loadsharing

Hi ibrahim,

load share the outbound traffic , does it means "TRAFFIC LEAVING UR AS TOWARDS UPSTREAM ISP's"? while the inbound traffic or download means traffic enter ur AS Number???

Yes, you are absolutely correct. If we are talking in regards to your AS then outbound means leaving your AS and inbound means entering your AS.

Regards, Kishore

Re: BGP Loadsharing

Hi Ibrahim (again )

I do not know the setup of your LAN , since you have provided us only your internet edge routers but you can also think of the GLBP to share the traffic from your LAN to the internet.

GLBP is similar to the more common HSRP and you can find more info to the next link

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html

If you want to load share the inbound traffic (from the internet to your lan) you could use the relevant BGP attributes to the public subnets adverstised to your ISP (i.e. as path prepend or med). However, this is sth that you have to discuss with your provider since many ISP override the assigned BGP attributes.

Hope that helps,

Vasilis

703
Views
20
Helpful
15
Replies
CreatePlease login to create content