Re: Traffic threshold for BGP?
Jennifer,
I don't have the answer, but just some thoughts.
1. Offtopic--just a little bit: You can get about 1x10mb atm pipe for
what 4 T1s cost you {typically of course depending on where you
are}. You may want to check on that. Also, why {even from a mgt.
standpoint} would you want to use your smaller pipes, when they are
not cost effective compared to 45mb? My only thought is you have the
DS3 to a non-backbone ISP it's just a peering point w/ another
company?...Just guessing...
2. BGP4 will do load balancing: Caveat: You have to use Loopback
interfaces at both ends. See:
http://www.cisco.com/warp/public/459/13.html
and do a ctrl-f {find} and search for "ebgp multihop"
but the best example is at:
http://www.cisco.com/warp/public/459/12.html
3. Did a lot of reading on BGP never saw load determinants. IE: at
60% go to DS3. BGP is all about shortest path. _It is a DV protocol
after all_. Only instead of shortest path, it uses shortest AS set.
However, you can set weight, if you know the AS you get/send certain
trafic to. This can be applied to the inbound outbound See:
http://www.cisco.com/warp/public/459/14.html
search for "Weight Attribute"
For outbound only, see Local Preference right below, same bat channel.
But again, not a BGP guru...so if someone can point you to a load
determinant factor...pass the link on if you would. ;-)
TroyC
On 14 Aug 2000 21:18:11 -0400, [EMAIL PROTECTED] ("Jennifer Mellone")
wrote:
Here is our BGP setup with a single ISP:
external 7507 router (EBGP, AS yyy))
||
| 4 T1's | 1 DS3
||
ISP router#1 ISP router#2
(AS xxx) (AS xxx)
Here's what's happening: All inbound/outbound traffic is going through the
DS3, and no traffic is going through the T1s!
Here's what the manager wants: Load balancing with the DS3 and T1s (T1's not
a backup mechanism). He wants all 5 circuits to be used all the time. He
wants the T1's to be used first, for example, and when the load reaches 50%
on them (or any other %), the DS3 gets used. Kind of like dialer-load
threshold with ISDN ;-) I'm not aware of anything like that, are you? He
specifically wanted me to ask that question...
But I was thinking that the only way you could do load sharing is have the
T1's be preferred outbound (higher local-pref than DS3) and the DS3 inbound
(lower MED than T1). Currently on the router the route-maps set both
local-pref and MED inbound/outbound on all circuits! Not very clean.
- Jennifer Mellone, BGP rookie
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2nd time...Passed BSCN Review {long}
For what it's worth, posting a second time...
{Posting thru nntp, if that matters?}
BSCN review
Test : BSCN 1.0
# of Questions: 61
Score : 850
Passing score : 690
Preperation : A bunch!
Exam Prep
Specifically, I took the BSCN 1.0 class through
IMS http://www.imsinc.com/ two weeks ago. Not
an indorsement, just stating where I went. The
class started off kind of rough, as the
instructor did not show up until 1pm on the
first day...travel probs. Additionally we had
a power outage for approximately 4 hours later
in the week. Luckily, I did not pay for the
class directly...work tuition reimbursement.
I took the test this past Thursday.
The class covered the meat of the material. I
think more importantly, it allowed you to
configure the commands on the routers. And at
this time, that worked out for me as my lab is
in a _Public Storage_ facility, until we move
into the house.
Self Study
BGP BGP BGP. Haven't done the ISP thing {yet!}.
This was my biggest lacking.
BTW, thanks go out to the 3 guys who replied
to my BGP Sync Next Hop thread. I wish it had
spawned a bit more conversation in the group...
thought it was a good question...ah well. ;-)
I gave OSPF about 1800 ticks of my study time,
due to experience. However, check the links
section at the bottom for OSPF stuff. All my
OSPF books are also in _Pub Storage_
facility, so I sorta winged it there, with
the class being my reinforcement.
EIGRP reinforcements actually came from the
course. And while I had experience with
EIGRP, I didn't know things like the HELLO/
Update/ Query/ Reply/ Ack packets. So if
you don't either...search Cisco. ;-)
VLSM...you are _EXPECTED_ to know it. Both for
the test and for the class. Not a problem for
me, but if you don't have it down tight, you
need to. Both the test the class EXPECT you
to know how to summarize {supernetting}.
Experience
First 10 years, I did long haul telecom. T1
guru, back when T1 was considered High speed.
Luckily I saw the writing on the wall, and
hi-jacked into the Networking scene 5 years
ago.
During those 5 years, I had to clean up other's
messes...5 users with a /24...that kind of stuff.
Discontiguous networks etc...all the while
integrating non-Cisco gear into the mix. So
I ended up buying 2 books from Amazon on OSPF,
had 10 days to figure it out implement it.
You either beat the learning curve or you
don't! ;-)
Well, that's about it. I got 100% on the IP portion;
I think that was the VLSM/Summarization. The funny
part was I got an 85% on OSPF, and 88% on BGP. Well,
it's funny to me, because I feel I should _know_ OSPF
better. ;-) Still wondering what I missed on OSPF.
BRCAN will be _my_ hard test. Half the time I mis-spell
TACACS ;-)
Good luck all...
and keep pressing the packets to the routes ;-)
TroyC
The links: {watch the word wrap}
==
http://www.cisco.com/warp/public/459/bgp-toc.html
which consists of:
http://www.cisco.com/warp/public/459/13.html
http://www.cisco.com/warp/public/459/14.html
http://www.cisco.com/warp/public/459/15.html
http://www.cisco.com/warp/public/459/16.html
http://www.cisco.com/warp/public/459/17.html
READ ALL THE ABOVE ^^ AT LEAST 5 TIMES
.
..
...then read it again! ;-)
Extra BGP links:
http://www.cisco.com/warp/public/459/21.html
thru
http://www.cisco.com/warp/public/459/27.html
http://www.cisco.com/warp/public/459/29.html
http://www.cisco.com/warp/public/104/
** http://www.cisco.com/warp/public/104/4.html
http://www.cisco.com/cpress/cc/td/cpress/design/ospf/on0407.htm
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Cisco vulnarabilities
Well,
Threw out that BGP4 confussion I had, and thought I would pass on some
info:
Fairly new GSR bug {August 3rd}.
http://www.securityfocus.com/frames/?content=/vdb/bottom.html%3Fvid%3D1541
And for general Cisco IOS bugs:
http://mail.altavista.com/jump/http://www.securityfocus.com/frames/?content=/vdb/middle.html%3Fvendor%3DCisco%26title%3D%26version%3Dany
watch the word wrap on both of those.
TroyC
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Re: Who wants to be a CCIE... Challenge Question
Real quick...not seeing the whole config...
"ip classless"
TroyC
On 11 Jun 2000 22:55:21 -0400, [EMAIL PROTECTED] ("Rodgers Moore")
wrote:
Hi all,
An update. I made a mistake on the configs. The mistake can easily be
found in a book. Since no one has found it, I won't spoil the fun and tell.
I'll just say, it's an ommission (twice).
Rodgers Moore
""Rodgers Moore"" [EMAIL PROTECTED] wrote in message
8i18s9$jff$[EMAIL PROTECTED]">news:8i18s9$jff$[EMAIL PROTECTED]...
It's been a while since a Friday Follies was done and there's alot of fear
over CCIE, etc. becoming "paper" certs. So I though I'd combine the two
concepts an post a challenge. Here's two router configurations that might
challenge the best of us. Just figure out what's wrong with them and send
me your answer(s). I will not post the answer(s) or give any hints etc.,
but I will tell you if you're right. Think of it like an NDA. Oh, and
believe me, the answer(s) won't be found in any book.
(sounds like the lab to me)
Overview: Two routers are configured for redundancy for users on a token
ring network. The serial 0's are both connected to the same location.
EIRGP is the routing protocol for the token ring and serial interfaces.
(There is more configuration, but that's not necessary to answer the
challenge)
Router A
interface lo0
ip address 10.1.254.1 255.255.255.0
interface e0
ip address 10.0.1.1 255.255.255.0
interface to0
ip address 10.1.1.1 255.255.255.0
standby 1 priority 200 preempt
standby 1 ip 10.1.1.3
standby 1 track s0 51
interface s0
ip address 10.1.0.1 255.255.255.252
router eigrp 1
passive-interface e0
network 10.0.0.0
Router B
interface lo0
ip address 10.1.253.1 255.255.255.0
interface e0
ip address 10.0.2.1 255.255.255.0
interface to0
ip address 10.1.1.2 255.255.255.0
standby 1 priority 150
standby 1 ip 10.1.1.3
interface s0
ip address 10.1.0.5 255.255.255.252
router eigrp 1
passive-interface e0
network 10.0.0.0
Enjoy!
Rodgers Moore, CCDP, CCNP-Security
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Re: HSRP/Load Balancing
Nat, This is one of those things that differientiate [sp?] a _LOGICAL_ drawing and a _PHYSICAL_ drawing.Figure 9-3 on that page shows "Network 3.0.0.0" and "Network 2.0.0.0" This is a logical drawing. These networks could be utilizing a HUB, Switch, or a direct connect such as a cross-over cable. Typically, in the real world [assuming you meant in a production enviroment] it is a switch. Now, let's assume it is a switched network. The switch wouldn't send out any "hello" type packets. The HRSP protocol is a _router_ protocol. So the routers are talking to each other, ensuring the primary is alive and well, and if not, a take over by the secondaries. The switch is just the medium. But this brings up another question that I had not found until you posted the link. And that was what about layer-2? IE: MAC address resolution. How did a switch, using VLANs quite possibly, ensure it went to the correct MAC address? From that link: ..." When you configure HSRP, the router automatically selects one of the virtual MAC addresses from a range of addresses in the Cisco IOS software that is within the range of Cisco's MAC address block"... Aha! So the MAC address stays the same [as does the associated IP address] But wait! How does the switch _relearn_ where that MAC address is? In other words: Primary router A, with IP of 1.1.1.1 and Mac adder of x:x:x:x is off switch port 5. Router A dies, and Router B takes over...using IP 1.1.1.1 and Mac adder of x:x:x:x now on switch port 8. But the switch still thinks x:x:x:x is on switch port 5. How does he get updated?? [besides arp table purge] Yet to figure this one out...but I will keep you updated, as I have been put on the HA [High Availability] Project where I work. FWIW, We are also looking at Cisco's Local director, F5's BigIP/3DNS, and a combination of pure physical redundancy. Troy Coulombe Network Engineer, CCNA ...and all around nice guy On 28 May 2000 03:17:35 -0400, [EMAIL PROTECTED] wrote: Hola newbies. I had a question that went unanswered a while back about load balancing and backup. I found the answer to it tonight. See this link for information: http://www.cisco.com/cpress/cc/td/cpress/ccie/ndcs798/nd2022.htm#xtocid185122 Now for those of you in the real world.no where in this doc do I see a switch. If there were one, do you just tell it to accept traffic from any of the routers, and are there weights or values to do this? Does the switch send some kind of hello packet to find out who the main router is or what??? Thanks! Nat CCNA. MCSE, CNA ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] --- ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
