Carlos - I monitor the board and attempt to ensure that most questions
are answered.
Keep in mind - this is a FREE - and "best effort" list. We're here to
help you, but have never committed any sort of "guaranteed mentoring".
If you are in need of some mentoring or 1-on-1 assistance, please
email me directly.
Regards,
Wayne A. Lawson II - CCIE #5244
President & Founder - IPexpert, Inc.
Email: [email protected]
Mobile: 810.334.1564
* For my SMS vCard Text WLAWSON to 50500
:: Message sent from iPhone.
On Jun 8, 2009, at 1:54 PM, "Joe Astorino" <[email protected]>
wrote:
Hi Carlos,
First off, I apologize if you have not had questions answered in a
timely fashion in the past. I know that since I came on board I try
to answer everybody's questions as soon as I can. With that being
said, lets look at your question.
OK first of all, lets talk about load balancing. I think you might
have the wrong idea here. If you have 2 links, say like you have
between R6 and R9 and you peer using the loopback address, you won't
have load balancing from a BGP perspective. Remember BGP will only
select the 1 best path by default...so in this case, if you did peer
using the loopback, your best path would always be via that loopback
address, which would be looked up in your IGP...now if your IGP has
equal cost metrics to that loopback address, yes it will load balance.
Looking ahead to 4.2 you are asked to make sure certain traffic goes
through 1 link and certain traffic goes through the other link. To
do this in BGP they are looking for load balancing actually within
BGP. To do that you need to have more than 1 path first of all...so
you need to have 2 seperate peerings. Secondly, you need to modify
BGP to make sure you tell it to use more than 1 path with the max-
paths command.
When you look at the routing table you should see the next hop via
the links it specifies. Does this help? If you have any more
questions don't hesitate to post back.
Regards,
Joe Astorino
CCIE #24347 (R&S)
Sr. Support Engineer – IPexpert, Inc.
URL: http://www.IPexpert.com
From: Carlos Valero [mailto:[email protected]]
Sent: Monday, June 08, 2009 1:48 PM
To: Edward''Bodnar; 'Bryan Bartik'; Joe Astorino
Cc: [email protected]
Subject: Re: [OSL | CCIE_RS] IPE Vol3 Lab 4 Task 4.1
I have not had any luck with my questions so far.
That is, nobody answers them.
So I quit wasting my time sending questions.
But I hope I have better luck this time, because I would like to get
an explanation for this one.
I don't quite understand part of the answer to Task 4.1
Specifically, I'm referring to the BGP session between R6 & R9.
Both Serial Links are active in this case:
R6
interface Serial0/0
ip address 144.44.60.6 255.255.255.0
!
interface Serial0/1
ip address 144.44.61.6 255.255.255.0
R9
interface Serial0/0
ip address 144.44.60.9 255.255.255.0
!
interface Serial0/1
ip address 144.44.61.9 255.255.255.0
And are being asked to configure a IBGP session between these two.
Since we have 2 links between this pair of Routers,
then it would make a lot more sense to establish the BGP session
using the Loopbacks, so that we get Load Balancing, correct?
Load Bal. is not a requirement in this case, but as far as I know,
that's always the Best Practice anyway.
However, the solution does NOT do that.
Instead, it just creates 2 separate sessions:
R6
router bgp 96
neigh 144.44.60.9 remote 96
neigh 144.44.61.9 remote 96
R9
router bgp 200
neigh 144.44.60.6 remote 96
neigh 144.44.61.6 remote 96
Question is: Is there any VALID reason why you are doing this here?
Thank you!
--- On Mon, 6/8/09, Joe Astorino <[email protected]> wrote:
From: Joe Astorino <[email protected]>
Subject: Re: [OSL | CCIE_RS] IPE vol2 lab 3
To: "'Bodnar, Edward'" <[email protected]>, "'Bryan Bartik'" <[email protected]
>
Cc: [email protected]
Date: Monday, June 8, 2009, 11:48 AM
Hey Ed,
1) You need to use this command if you are using Auto-RP in a sparse-
mode environment
2) Basically here is the idea -- OK, think about how Auto-RP works,
it uses dense mode to propogate the RP information using 224.0.1.39
and 224.0.1.40.....so by design the information is
propogated throughout the entire multicast domain. When you use
sparse mode, it basically breaks this concept...because you are not
requesting the groups you will not get them. What the command does
is sort of a "hack." It allows you to use Auto-RP even though you
are using sparse mode. Essentially it says "For 224.0.1.39 and 224.0.1.40
I am allowed to use dense mode, for everything else use sparse mode"
HTH,
Regards,
Joe Astorino
CCIE #24347 (R&S)
Sr. Support Engineer – IPexpert, Inc.
URL: http://www.IPexpert.com
From: [email protected] [mailto:[email protected]
] On Behalf Of Bodnar, Edward
Sent: Sunday, June 07, 2009 8:30 PM
To: 'Bryan Bartik'
Cc: [email protected]
Subject: Re: [OSL | CCIE_RS] IPE vol2 lab 3
I have a question about “ip pim autorp listener”
1. When do I need to use this sparce-mode only ? sparce-
dense-mode
2. What does this command do. I take it off my configuration
and it seems to be working without it.
ED,
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