I *personally* would prefer OSPF for the following.. 1. Easier addressing, IS-IS feels like doing HEX 2. Security wise, OSPFv3 does better peer authentication using IPsec, the last i checked, IS-IS can only do MD5 which is easy to crack. 3. For Vendor support, Both are open standard and the big boys in the service provider space support both protocols so its easy to have a mix of Cisco, juniper, Huawei without much issues.... My two cents.. Kind regards On Wed, Aug 24, 2016 at 3:36 PM, Kennedy Aseda via skunkworks < skunkworks@lists.my.co.ke> wrote:
In terms of functionality, I do not think either has advantage over the other. However there could be reasons why one would prefer one IGP over the other:
1. Provider network environment - do all you equipment support the IGP? Vendor support for the IGP in relation to MPLS TE and other technologies you want to support.
2. Availability of technical expertise for the IGP
3. Ease of deployment and scaling. ISIS is easier to deploy and scale on IPv4/IPv6 dual stack environment compared to OSPF which requires separate processes and area design.
It's a matter of organization choice in my opinion
On 24 Aug 2016 15:04, "Thuo Wilson via skunkworks" < skunkworks@lists.my.co.ke> wrote:
In other words, ISIS is no superior. Or are we comparing mangoes and oranges
@Wash, bona unaweka kufuri/li?
Kind Regards, Wilson./
On 24 August 2016 at 12:39, Alex Watila via skunkworks < skunkworks@lists.my.co.ke> wrote:
Roflol,
Admin wash, please let us learn
Regards,
Alex
*From:* Odhiambo Washington via skunkworks [mailto: skunkworks@lists.my.co.ke] *Sent:* Tuesday, August 23, 2016 10:09 PM *To:* Michuki Mwangi <michuki.mwangi@gmail.com>; Skunkworks Mailing List <skunkworks@lists.my.co.ke> *Subject:* Re: [Skunkworks] OSPF vs ISIS - Which do you prefer and why
This topic is now closed. I think it sould have gone to the EaNOG list :-)
Sababu it sounded like me listening to a math teacher after a lunch of Ugali na mandondo!
On 23 August 2016 at 21:56, Michuki Mwangi via skunkworks < skunkworks@lists.my.co.ke> wrote:
Hi Both,
Both are IGP and use distance vector. The main difference between that OSPF is dependent on IP and ISIS is connectionless. LSA's and other stuff aside.
Both are used on core SP network to carry infrastructure and loopback prefixes period. Configuring IGP's to carry customer prefixes, Internet prefixes, etc is what makes them bulky. In turn IGP will occupy CPU cycles trying to continuously converge where they don't need to. If you carry your infrastructure and loopbacks using an IGP, they converge faster, database is mostly stable and they use less CPU.
Why OSPF over ISIS. In a multivendor environment you are more likely to find OSPF support than ISIS. For instance i would be curious to find out if the router board vendors have ISIS support. In a single or dual vendor environment you are likely to have support for ISIS. ISIS is relatively easier to deploy/support for most people, hence the reason why large single/dual vendor networks prefer it over OSPF.
My 2 cents.
Michuki.
On Tue, Aug 23, 2016 at 4:45 PM, Michael Bullut via skunkworks < skunkworks@lists.my.co.ke> wrote:
Hey Thuo,
What routers have you worked with?
On the provider's end *(POP side),* I've worked with:
1. *Cisco ASR 1006.* 2. *Cisco 7200.* 3. *Cisco 3600.* *(In a rare instance)*
On the client's end, I've worked with:
1. *Cisco 2800 & 2900.* *(Mostly used for redundancy setups)* 2. *Cisco 1800 & 1900.* *(Mostly used for single last-mile circuits)* 3. *Cisco 800.* *(Worst CE device I've ever worked with)*
Warm regards,
Michael.
On 23 August 2016 at 16:10, Thuo Wilson <lixton@gmail.com> wrote:
Kind Regards,
Wilson./
On 23 August 2016 at 16:02, Michael Bullut <main@kipsang.com> wrote:
Greetings Wilson,
While I haven't worked with IS-IS before but the only disadvantage I've encountered with OSPF is that it is resource intensive on the router it is running on which is why only one instance runs on any PE & P device on an ISP network. OSPF is pretty good in handling the core network routing while BGP & EGP handle the last-mile routing between PE & CE devices. BGP & EGP can run on top of OSPF.
Warm regards,
Michael.
Though, below is also true, we dont run a cisco2800 on core network.
Overload Mechanism – IS-IS has the ability to set the Overload (OL) bit in its LSAs. This results in other routers in that area treating this router as a leaf router in their shortest path trees, which means that its only used for reaching the directly connected interfaces and is never placed on the transit path to reach other routers. So does this happen any more? No, it doesnt. This feature was required in the jurassic age when routers came with severely constrained memory, CPU power and the original intention of the OL mechanism is now mostly irrelevant. Most core routers today have enough memory and CPU that they will not get inundated by the IS-IS routes in any sane network design.
On 23 August 2016 at 15:34, Thuo Wilson via skunkworks < skunkworks@lists.my.co.ke> wrote:
Network Admins,
I Once went for an interview as a Core Network Admin in one of the major telcos in KE and asked which protocol i preferred and why.
Am sure am not the only one and won't stop here.
Though i gave my own reasons, a panelist insisted ISIS is superior and gave his reasons by grinning but not explaining to an interviewee [me of course]. Sadly i didn't get the job, probably because *i asked him* WHY he think isis is superior that OSPF :(
I came across this URL http://bit.ly/2bsqJCA when scrolling the web today, one year later - i still wanted to find out if am the only one who thinks its a matter of choice btwn the 2. Although there isn't distinct 1:1 argument, its good we discuss it here and figure out why one prefer one over the other - *consider a FLAT huge network.*
Kind Regards,
Wilson./
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