From: Mujeeb Sarwar (mujeebsarwar@gmail.com)
Date: Mon Dec 22 2008 - 03:39:14 ARST
Sample Conf.
Scenario 1
For outbound just ask your upstream providers to send the desired routes as
discussed above and add 'maximum-path 2' command in BGP configuration.
******************************************************
router bgp 65001
neighbor y.y.a.a remote-as 65002 ( ISP A )
neighbor y.y.b.b remote-as 65003 ( ISP B )
network 10.1.1.0 mask 255.255.255.0
network 192.168.1.0
neighbor y.y.a.a route-map PREP_A out ( Both subnets will be advertised to
ISP A with 10.1.1.0/24 having prepended AS-PATH )
neighbor y.y.b.b route-map PREP_B out ( Both subnets will be advertised to
ISP B with 192.168.1.0/24 having prepended AS-PATH )
maximum-paths 2
access-list 1 permit 10.1.1.0 0.0.0.255
access-list 2 permit 192.168.1.0 0.0.0.255
route-map PREP_A permit 10
match ip address 1
set as-path prepend 65001 65001
route-map PREP_A permit 20
route-map PREP_B permit 10
match ip address 2
set as-path prepend 65001 65001
route-map PREP_B permit 20
**************************************************
Regards,
Mujeeb
On Sun, Dec 21, 2008 at 7:20 PM, Akber Ali Mirza
<akberali.cisco@gmail.com>wrote:
> Dear Mujeeb,
>
> My Sincere thanks for your Great explanation! ( I couldn't have get better
> than this!)
>
> Could you plz help me in building the configurations for my both scenarios.
>
> Thanks to John/Richard for your valuable explanation.
>
> I really looking forward to try this scenarios in my Lab .
>
>
> Many Thanks!
> Akber
>
> On Sun, Dec 21, 2008 at 11:52 AM, Mujeeb Sarwar <mujeebsarwar@gmail.com>wrote:
>
>>
>> Dear Akber,
>>
>> Scenario 1
>>
>> OUTBOUND Load balancing:
>>
>> You can ask *ISP A* to originate a default route through BGP plus ask *ISP
>> B* to send partial BGP routes. So in this case traffic which would match
>> with specific routes will take ISP B path and rest of the traffic will take
>> ISP A. In this case you will achieve load balancing for OUTBOUND traffic.
>>
>> If you are getting full BGP feed from both ISPs then you can use
>> 'maximum-path 2' to install both routes in routing table.
>>
>>
>> INBOUND Load Balancing:
>>
>> As per you requirement you want to recieve traffic for 10.1.1.0/24 (
>> Assuming that these are Public IP Subnets in actual and there would be
>> NATing on Firewall ) from one ISP and for 192.168.1.0/24 from other with
>> backup. For this you can advertise both of your subnets through BGP to both
>> ISPs and do *AS-PATH prepending* to make a subnet less preferable through
>> one ISP while providing backup as well in case of failure.
>>
>>
>> Scenario 2:
>>
>> OUTBOUND Load Balancing:
>>
>> Now in this scenario where you have 2 different Routers on which Internet
>> links are coming, outbound load balancing will depend upon traffic flow from
>> Firewall to Routers. Let say you are using GLBP between both Internet
>> Routers and firewall is forwarding traffic to gateway ( Virtual IP Address )
>> then traffic will be forwarded to both Routers from Firewall. Now in this
>> case you have option to recieve Default Route/Full BGP Routes/Partial Routes
>> from both ISPs.
>>
>> Note that you can't use 'maximum-path' here because both internet links
>> are terminating on 2 different roouters.
>>
>> INBOUND load Balancing:
>>
>> Configuration options will remain same as 'Scenario 1' but you need
>> to configure static routes on both Routers for both subnets toward firewall
>> so that return traffic from Internet could be forwarded to firewall if
>> recieve from any of the Internet link.
>>
>>
>> Regards,
>>
>> Mujeeb
>>
>> On Sun, Dec 21, 2008 at 7:22 AM, darth router <darklordrouter@gmail.com
>> > wrote:
>>
>>>
>>> http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800945bf.shtml
>>>
>>>
>>> On Sat, Dec 20, 2008 at 5:48 PM, Akber Ali Mirza
>>> <akberali.cisco@gmail.com>wrote:
>>>
>>> > John-
>>> >
>>> > Thanks for the valuable input.
>>> >
>>> > Can you tell how do i go ahead for configuring BGP loadbalancing in the
>>> > below scenario:-
>>> >
>>> >
>>> > Internal Network--------->> Internet Router A ------------>>ISP A
>>> > (10.1.1.0/24/ Internet Router B-------------->>ISP B
>>> > 192.168.1.1.0/24)
>>> > I want my 10.1.1.0 subnet to pass through only ISP A & 192.168.1.0
>>> subnet
>>> > to
>>> > pass through ISP B.
>>> >
>>> > But If one ISP goes down traffic should be diverted to other traffic
>>> with
>>> > out diversion.
>>> >
>>> > Also one major reason why i am looking for Loadbalancing with Service
>>> > provider is
>>> > for example latency towards ISP A is very high , then let me know what
>>> > needs
>>> > to be done form my end on the Internet Routers. IS there any way we can
>>> > achieve this with out any changes on BGP.
>>> >
>>> > Any scenario with commands would help me a lot
>>> >
>>> > Cheers!
>>> >
>>> >
>>> >
>>> >
>>> > On Sun, Dec 21, 2008 at 5:38 AM, John <jgarrison1@austin.rr.com>
>>> wrote:
>>> >
>>> > > You could set the weight of the routes from both ISP's to the same
>>> value,
>>> > > but obviously if ISP A has a route that ISP B doesn't than you'll get
>>> no
>>> > > load sharing for that route
>>> > > ----- Original Message ----- From: "Akber Ali Mirza" <
>>> > > akberali.cisco@gmail.com>
>>> > > To: "John" <jgarrison1@austin.rr.com>
>>> > > Cc: <ccielab@groupstudy.com>
>>> > > Sent: Saturday, December 20, 2008 4:00 PM
>>> > >
>>> > > Subject: Re: BGP Loadsharing
>>> > >
>>> > >
>>> > > John -
>>> > >>
>>> > >> My Questionhere is as follows below .
>>> > >>
>>> > >> Internal Network 2 subnets----Internet Router ----connected
>>> > >> to-------->ISPA
>>> > >> & ISP B service
>>> > >> Provider.
>>> > >> ( ISP BW =2 mb each)
>>> > >>
>>> > >> How do i perform Loadsharing using BGP on my internet router ?
>>> > >> ( How both the links will be utilized by using BGP in this scenario
>>> )
>>> > >>
>>> > >> Cheers!
>>> > >>
>>> > >>
>>> > >> On Sun, Dec 21, 2008 at 2:02 AM, John <jgarrison1@austin.rr.com>
>>> wrote:
>>> > >>
>>> > >> You really don't provide enough information to answer the question.
>>> If
>>> > >>> your running BGP as your igp you can set one of the appropriate
>>> > community
>>> > >>> attributes on both ingress routers and send-community to your ibgp
>>> > peers.
>>> > >>> As
>>> > >>> far as return paths that would depend on what your outside
>>> addresses
>>> > are
>>> > >>> and
>>> > >>> how their being advertised by your ISP's.
>>> > >>>
>>> > >>> How does the internal network make routing decisions? You really
>>> don't
>>> > >>> want router A or B making the load sharing desciscion, so unless
>>> you
>>> > >>> really
>>> > >>> are running BGP as your igp your looking at the wrong solution
>>> > >>> ----- Original Message ----- From: "Akber Ali Mirza" <
>>> > >>> akberali.cisco@gmail.com>
>>> > >>> To: <ccielab@groupstudy.com>
>>> > >>> Cc: <akberali.cisco@gmail.com>
>>> > >>> Sent: Saturday, December 20, 2008 12:47 PM
>>> > >>> Subject: Re: BGP Loadsharing
>>> > >>>
>>> > >>>
>>> > >>> Hi Experts,
>>> > >>>
>>> > >>>>
>>> > >>>> Please provide your valubale help on the below query.
>>> > >>>>
>>> > >>>> Thanks ,
>>> > >>>> Akber.
>>> > >>>>
>>> > >>>> On Sat, Dec 20, 2008 at 2:33 AM, Akber Ali Mirza
>>> > >>>> <akberali.cisco@gmail.com>wrote:
>>> > >>>>
>>> > >>>> Hi Experts,
>>> > >>>>
>>> > >>>>>
>>> > >>>>> Please help me in configuring BGP Load balancing. { Sorry from
>>> > >>>>> Diverting
>>> > >>>>> from the CCIE forum }
>>> > >>>>>
>>> > >>>>>
>>> > >>>>> Scenario1:-
>>> > >>>>> 192.168.1.0/24 Vlan 10 ------->
>>> > >>>>> 10.0.1.0/24 Vlan 20 ------> both vlan levaraging CoreSwitch
>>> > >>>>> ----->
>>> > >>>>> F/W ---> Internet Router -------> ISP A 2MB
>>> > >>>>>
>>> > >>>>>
>>> ------->
>>> > >>>>> ISP B 2MB
>>> > >>>>>
>>> > >>>>> Scenario2:-
>>> > >>>>> 192.168.2.0/24 Vlan 10 ------->
>>> > >>>>> 10.0.2.0/24 Vlan 20 ------> both vlan levaraging CoreSwitch
>>> > >>>>> ----->
>>> > >>>>> F/W ---> Internet Router A -------> ISP A 2MB
>>> > >>>>>
>>> > >>>>> Internet
>>> > >>>>> Router B ------> ISP B 2MB
>>> > >>>>>
>>> > >>>>> Requirement:- How do i configure Load balancing using BGP for
>>> which
>>> > >>>>> both
>>> > >>>>> my vlans should use Service Provider A& B on a Load Balancced
>>> > purpose.
>>> > >>>>> Please share me the best industry standards as well.
>>> > >>>>>
>>> > >>>>> Also please explain me how the return traiffc will reach into my
>>> > >>>>> network.
>>> > >>>>>
>>> > >>>>> Thanks in Advance!
>>> > >>>>> Akber.
>>> > >>>>>
>>> > >>>>>
>>> > >>>>
>>> > >>>> Blogs and organic groups at http://www.ccie.net
>>> > >>>>
>>> > >>>>
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>>> > >>>
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>>> > >>
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