RE: The Internet core router
yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The Internet core router
I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
From what I've heard, CCIE is considered a junior level cert when it comes to ISP's. Comments on this? ISP consider Juniper, Nortel, Lucent certs more appropriatewhereas CCIE would be more for the enterprise. Curtis Call wrote: I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ Get your FREE download of MSN Explorer at http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The Internet core router
It was the intent to prepare a written exam that when passed indicates a strong readiness for the lab test. Essentially, the difficulty levels between the written and lab are designed to be comparable, whereas Cisco's written isn't on the same level as its Lab. pete *** REPLY SEPARATOR *** On 3/14/2001 at 9:02 AM Curtis Call wrote: I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The Internet core router
Is the exam actually more demanding, or is the content just different? For example, whereas the CCIE concentrates on SNA, RSRB, and token ring, I'd imagine that Juniper concentrates more on ISIS, BGP, and MPLS. Is this the case? If not, in what way is the Juniper exam more difficult than the CCIE exam? Craig At 09:02 AM 3/14/2001 -0700, you wrote: I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The Internet core router
Is the exam actually more demanding, or is the content just different? For example, whereas the CCIE concentrates on SNA, RSRB, and token ring, I'd imagine that Juniper concentrates more on ISIS, BGP, and MPLS. Is this the case? If not, in what way is the Juniper exam more difficult than the CCIE exam? Craig I'd throw in the question -- does the exam consider things that aren't strictly configuration, but essential in the real world ISP environment? These might include: Address justification amd registration Defining policies for multihoming, interprovider peering, etc., understanding the addressing, registration, etc., requirements Single provider multihoming Hot and cold potato designs for provider networks Defining SLAs and then doing the traffic engineering to implement them Denial of service protection (both malicious and the just plain stupid, such as AS7007) These certainly get into "design" _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
I don't think that anyone at Juniper or ISP's for that matter would consider the CCIE cert as junior, or in any way lacking in technical difficulty. The issue is one of applicability. ISP's deal at some depth with IP routing which is about 1/2 at most of the CCIE program. As such, the cert doesn't by default convey the ideal skillset on behalf of its holder. Pete *** REPLY SEPARATOR *** On 3/14/2001 at 10:04 AM Net Bum wrote: From what I've heard, CCIE is considered a junior level cert when it comes to ISP's. Comments on this? ISP consider Juniper, Nortel, Lucent certs more appropriatewhereas CCIE would be more for the enterprise. Curtis Call wrote: I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ Get your FREE download of MSN Explorer at http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The Internet core router
I would say that the exam is more demanding. In my experience with Cisco tests, they expect you to know a wide breadth of information but the depth of knowledge required isn't very great. With the Juniper exam, their questions are much more focused, you won't know the answer unless you know the concept very well. Here is an example of a question (No, this is not from the test, I made it up myself) to illustrate the level of detail required: "When does an OSPF DR not advertise an LSA type 2?" If you know the answer, then you'd probably be comfortable taking the test. That is the level of knowledge required. http://www.juniper.net/training/certification/tcp_faqs.html#07 That shows the exam objectives of the Juniper exam. Yes, OSPF, IS-IS, BGP, and MPLS are a big part of the exam, just like the objectives show. It would be nice if there was a mailing list for the Juniper certs so that these messages wouldn't have to take up space on the Cisco list. Anyone know of one? At 01:07 PM 3/14/01, you wrote: Is the exam actually more demanding, or is the content just different? For example, whereas the CCIE concentrates on SNA, RSRB, and token ring, I'd imagine that Juniper concentrates more on ISIS, BGP, and MPLS. Is this the case? If not, in what way is the Juniper exam more difficult than the CCIE exam? Craig At 09:02 AM 3/14/2001 -0700, you wrote: I have taken the Juniper Internet Specialist Exam (multiple choice). If you're looking for a comparison, then I can say that it is a lot more demanding than any of the Cisco Exams I have taken as of yet. (CCNP, CCIE Written). At 03:25 AM 3/14/01, you wrote: yup there is http://www.juniper.net/training/certification/ i wonder how tough is the exam. anyone here took it? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Deepak Sharma Sent: Wednesday, March 14, 2001 2:20 PM To: sipitung Cc: Cisco group study Subject: Re: The Internet core router lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001902b6d33bdfc13c@[63.216.127.100]... I think that many ISP routers can be "core", not as in the core layer -- but an ISP router at any layer could be one of those described in the http://lightreading.com/testing Internet Core Router Test. I mean, first you have to define ISP and don't even think about saying "Tier 1" ISP because we've been through that one enough. Many ... "ISPs" ... use GSR 12000's for all their routing in a transit-AS (even Hotmail and Ebay). These are clearly peering or border routers. Juniper routers (from M5 to M160) will do great BGP and aggregate a lot of IP routes and a lot of interfaces (especially packet SONET), making it another great choice for ISP connectivity and peering. It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. IBGP runs in the core with full routes. Are you talking about MP-BGP? MPLS-TE doesn't bother with IBGP information directly (i.e. the constraint- based routing is for SPF calculations and doesn't factor into the BGP decision process or convergence). MPLS-TE and MPLS-VPN are pretty separate topics. Yes, you don't have to do MP-BGP in the core, but I am sure that since most ISP's use IBGP in the core, it's also MP-BGP (no bgp default ipv4-unicast). This is a the primary place for "core" routers from what I have seen. I mean, it is called the "core layer". An ISP POP access router might have the greatest number of BGP routes and paths, but not as much bandwidth requirements. If the POP router primarily deals with customers, it will advertise only default and partial routes to many of them. Only a small proportion of customers want full routes. A POP router will also generally accept only a small number of routes from customers. It sounds like you are describing the access layer, which may or may not have BGP at all. IP and circuit aggregation is more important here than transit or anything else IMO. "core" routers can also be placed at this layer, although they would be called "border" or "access" instead. Most of the "core" routers described in the test don't have enough integrated access and different types of interfaces to shine in the access layer. Technically, this should all be transport (Cable, DSL, ATM, Optical) for best use of resources and superior aggregation (PPPoE, PPPoA, PVC/PVP, VCI/VPI, and especially DWDM). The days of a separate router with a separate CSU/DSU with a separate circuit for each separate customer for access are hopefully long and gone. Interprovider routers at tier 1 are unlikely to need to exchange full routes Such routers are bandwidth-intense, but the definition of a tier 1 is that you exchange only customer routes (perhaps oversimplifying, but that's close) with other tier 1 providers. This is the peering situation I mentioned above. "core" routers definitely have a place here, but they would be called something else (e.g. "border"). I think there is even more places an ISP could find uses for a "core" router. For example, in the distribution layer, a "core" router could be used for IP aggregation, separation of IGP areas, route filtering, route dampening, etc ... to provide more flexible routing stability and control. So while the Foundry NetIron does not currently fit the bill for MP-BGP and MPLS-VPNs (or any MPLS for that matter), it could still easily do simple peering, simple distribution/control, etc. It also *could* do ISP core routing, but (as shown in the tests) Juniper and Cisco would make better choices. As you can see, I definitely agree there is no *best* "core" Internet router, because each has its own limitations and areas of excellence. -dre _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
Well, you're going to love this article. They increased the number of networks in the core of the Internet by 25 fold to do their BGP table capacity test!? Nonetheless, it's a very interesting and well-written article and set of tests, Please do let us know what you think after reading it in detail and talking to the author. Thanks. Priscilla At 10:03 PM 3/12/01, Howard C. Berkowitz wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung Just started looking at it tonight. I will be speaking with its author at the IETF meeting next week. I would think long and hard before I'd claim any router is the "best" core router. Individual numbers can be misleading. I have a draft out on single-router BGP convergence time, http://www.isi.edu/internet-drafts/draft-berkowitz-bgpcon-00.txt. It is fairly rough, but starts talking about the interactions of multiple parameters. Unfortunately, the appendix giving various ISP applications for BGP routers isn't in that draft, but will be in the next one. It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. An ISP POP access router might have the greatest number of BGP routes and paths, but not as much bandwidth requirements. If the POP router primarily deals with customers, it will advertise only default and partial routes to many of them. Only a small proportion of customers want full routes. A POP router will also generally accept only a small number of routes from customers. Interprovider routers at tier 1 are unlikely to need to exchange full routes Such routers are bandwidth-intense, but the definition of a tier 1 is that you exchange only customer routes (perhaps oversimplifying, but that's close) with other tier 1 providers. A revised draft will be presented at the IETF next week to the benchmarking methodology (BMWG) and inter-domain routing (IDR, responsible for BGP). This draft is coauthored by Alvaro Retana at Cisco, and Sue Hares and Padma Krishnaswamy at NextHop (the former GateD organization, which is the base for quite a number of implementations). Hopefully, we will also get a Juniper coauthor. The plan is that it will become a BMWG working group document in the standards track (well, as much as standards track applies to performance measurement documents, a subtlety of the IETF process). -- "What Problem are you trying to solve?" ***send Cisco questions to the list, so all can benefit -- not directly to me*** Howard C. Berkowitz [EMAIL PROTECTED] Technical Director, CertificationZone.com Senior Mgr. IP Protocols Algorithms, Advanced Technology Investments, NortelNetworks (for ID only) but Cisco stockholder! "retired" Certified Cisco Systems Instructor (CID) #93005 _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Priscilla Oppenheimer http://www.priscilla.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
Well, you're going to love this article. They increased the number of networks in the core of the Internet by 25 fold to do their BGP table capacity test!? The "number of routes in the core" is not a simple number, and they've presumably made some simplifying assumptions. As part of the draft I'm working on, we are coming up with some ways of estimating the load. Let's say the number of routes in a default-free table is D. Actually, this number will vary depending on where you measure it -- the weekly CIDR reports probe routers in Tokyo and London, and come up with slightly different sizes. In a large provider, you also have customer routes that are aggregated at the edges, as well as infrastructure routes. Our working number for the number of routes a large provider's internal number is on the order of 1.3 to 1.5 D. Another consideration is the number of paths per route. In other words, how many potential paths are there from which BGP will select one (not even beginning to get into complex policies). An informal rule of thumb is that there average 4 paths per route. The number of routes in the DFZ has returned to exponential growth. I don't have a current growth curve in front of me, but when the CIDR measures were instituted in 1991, the table was doubling every 5 to 9 months. A factor of 25 seems a little high, but, pessimistically, doubling every 5 months would stretch us out about two years. Historically, router capacity doubles about every 18 months. A substantial amount of this growth, incidentally, appears to be from more-specifics being injected for multihoming and traffic control, rather than completely new address space. It's a real matter of concern, because such injection is counter to the CIDR model. The existing routing system was never really designed to support fine-grained multihoming, and there are no short term alternatives that won't annoy significant numbers of organizations. Nonetheless, it's a very interesting and well-written article and set of tests, Please do let us know what you think after reading it in detail and talking to the author. Thanks. Priscilla At 10:03 PM 3/12/01, Howard C. Berkowitz wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung Just started looking at it tonight. I will be speaking with its author at the IETF meeting next week. I would think long and hard before I'd claim any router is the "best" core router. Individual numbers can be misleading. I have a draft out on single-router BGP convergence time, http://www.isi.edu/internet-drafts/draft-berkowitz-bgpcon-00.txt. It is fairly rough, but starts talking about the interactions of multiple parameters. Unfortunately, the appendix giving various ISP applications for BGP routers isn't in that draft, but will be in the next one. It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. An ISP POP access router might have the greatest number of BGP routes and paths, but not as much bandwidth requirements. If the POP router primarily deals with customers, it will advertise only default and partial routes to many of them. Only a small proportion of customers want full routes. A POP router will also generally accept only a small number of routes from customers. Interprovider routers at tier 1 are unlikely to need to exchange full routes Such routers are bandwidth-intense, but the definition of a tier 1 is that you exchange only customer routes (perhaps oversimplifying, but that's close) with other tier 1 providers. A revised draft will be presented at the IETF next week to the benchmarking methodology (BMWG) and inter-domain routing (IDR, responsible for BGP). This draft is coauthored by Alvaro Retana at Cisco, and Sue Hares and Padma Krishnaswamy at NextHop (the former GateD organization, which is the base for quite a number of implementations). Hopefully, we will also get a Juniper coauthor. The plan is that it will become a BMWG working group document in the standards track (well, as much as standards track applies to performance measurement documents, a subtlety of the IETF process). -- "What Problem are you trying to solve?" ***send Cisco questions to the list, so all can benefit -- not directly to me*** Howard C. Berkowitz [EMAIL PROTECTED] Technical Director, CertificationZone.com Senior Mgr. IP Protocols Algorithms, Advanced Technology Investments, NortelNetworks (for ID only) but Cisco stockholder! "retired" Certified Cisco Systems Instructor (CID) #93005 _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL
Re: The Internet core router
"dre" [EMAIL PROTECTED] wrote, ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001902b6d33bdfc13c@[63.216.127.100]... I think that many ISP routers can be "core", not as in the core layer -- but an ISP router at any layer could be one of those described in the http://lightreading.com/testing Internet Core Router Test. I mean, first you have to define ISP and don't even think about saying "Tier 1" ISP because we've been through that one enough. Many ... "ISPs" ... use GSR 12000's for all their routing in a transit-AS (even Hotmail and Ebay). These are clearly peering or border routers. Juniper routers (from M5 to M160) will do great BGP and aggregate a lot of IP routes and a lot of interfaces (especially packet SONET), making it another great choice for ISP connectivity and peering. It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. IBGP runs in the core with full routes. Depending on the design of the core, the routers at the edge of the core will use full routes to set up MPLS LSPs from one side of the core to the other, but routers internal to the core may not need it if they are under LDP or RSVP-TE control from the edge routers. Are you talking about MP-BGP? MPLS-TE doesn't bother with IBGP information directly (i.e. the constraint- based routing is for SPF calculations and doesn't factor into the BGP decision process or convergence). MPLS-TE and MPLS-VPN are pretty separate topics. Yes, you don't have to do MP-BGP in the core, but I am sure that since most ISP's use IBGP in the core, it's also MP-BGP (no bgp default ipv4-unicast). This is a the primary place for "core" routers from what I have seen. I mean, it is called the "core layer". If you think of the core as interconnecting the POP/access and server sites inside an ISP or an enterprise, there's a good deal of interest in subsecond reconvergence times. This probably is achievable with link state IGPs, using millisecond or microsecond hellos (or relying on hardware failure detection on optical links), and more advanced algorithms than the 40-year-old Dijkstra. In the short to moderate term, there is no foreseeable way to get convergence times this fast with exterior routing. Actually, superfast convergence in the global Internet may be a Really Bad Idea with respect to Internet stability. An ISP POP access router might have the greatest number of BGP routes and paths, but not as much bandwidth requirements. If the POP router primarily deals with customers, it will advertise only default and partial routes to many of them. Only a small proportion of customers want full routes. A POP router will also generally accept only a small number of routes from customers. It sounds like you are describing the access layer, which may or may not have BGP at all. If the customers want to multihome to multiple providers, or even to multiple POPs of the same provider, BGP is really the only game in town. I agree that single-homed customers don't need it, and, for some situations, multiple defaults will work at the cost of suboptimal routing. IP and circuit aggregation is more important here than transit or anything else IMO. "core" routers can also be placed at this layer, although they would be called "border" or "access" instead. Most of the "core" routers described in the test don't have enough integrated access and different types of interfaces to shine in the access layer. Technically, this should all be transport (Cable, DSL, ATM, Optical) for best use of resources and superior aggregation (PPPoE, PPPoA, PVC/PVP, VCI/VPI, and especially DWDM). The days of a separate router with a separate CSU/DSU with a separate circuit for each separate customer for access are hopefully long and gone. This is a huge discussion right here. I agree that a very high density of logical interfaces is the requirement for an ISP "edge" rather than "core" router. The aggregation to these interface may very well be in what variously is called the access or collection tier. While there's no industry consensus on terminology for the hierarchy associated with ISPs, Cisco has been getting away from core/distribution/access in some of its carrier-oriented presentation. The newer usages seem to be: access: customer site routers, which may either be customer provided (CPE)or carrier provided at the customer location (CLE). collection: the broadband access network (DSL, cable, etc.), which may aggregate into VLANs, etc. distribution or edge: POP, possibly interprovider interconnect, at least some servers (e.g., cache) core: intraprovider backbone I will be co-organizing a session this June at the Internet Society
Re: The Internet core router
couple comments inserted Howard It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. dre IBGP runs in the core with full routes. Are you talking about MP-BGP? MPLS-TE doesn't bother with IBGP information directly (i.e. the constraint- based routing is for SPF calculations and doesn't factor into the BGP decision process or convergence). MPLS-TE and MPLS-VPN are pretty separate topics. Yes, you don't have to do MP-BGP in the core, but I am sure that since most ISP's use IBGP in the core, it's also MP-BGP (no bgp default ipv4-unicast). I think the 2547 relationship had more to do with the fact that P routers use significantly less BGP provided information than do PE's. Essentially, it's only the PE routers than maintain BGP routing info pertinent to the networks (C) which they interconnect while the P routers use a less inclusive BGP with IGPs and MPLS to provide transparent transit.I expect Howard was referring to the IGP dependencies not on their ability to populate traffic engineering databases, but rather for stability/scalability/convergence times based on the fact that a core of this nature would depend heavily on these algorithm. Furthermore, its quite possible, though I haven't seen it done, to create a BGP less core that simply uses MPLS -with optional TE- to forward between edge BGP devices. In such a case, the requirements for the "core" routers do not include BGP table capacity or forwarding performance during instability etc whereas the "edge" router requirements do. I think overall, the point that the term "core" lacks precision is very accurate. Pete _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001905b6d4554abd7f@[63.216.127.100]... Depending on the design of the core, the routers at the edge of the core will use full routes to set up MPLS LSPs from one side of the core to the other, but routers internal to the core may not need it if they are under LDP or RSVP-TE control from the edge routers. If you think of the core as interconnecting the POP/access and server sites inside an ISP or an enterprise, there's a good deal of interest in subsecond reconvergence times. This probably is achievable with link state IGPs, using millisecond or microsecond hellos (or relying on hardware failure detection on optical links), and more advanced algorithms than the 40-year-old Dijkstra. In the short to moderate term, there is no foreseeable way to get convergence times this fast with exterior routing. Actually, superfast convergence in the global Internet may be a Really Bad Idea with respect to Internet stability. I don't think I've seen POP/access or server sites that are implementing subsecond reconvergence (especially on the collocation side) with even IGPs at this point. Combining this with some of the other concepts you brought up is very key. To add another one into the mix, try to solve the problem of stateful failover using "n to many" clustering/high-availability for servers in these environments. Bringing this to the network layers becomes difficult when considering multiple paths and convergence, be it long-haul, metro, or even across logical local areas (VLANs) at the lower network layers, or external or internal routing at the higher network layers (IGP, MPLS-TE, Content routing, Content switching, etc). This is a huge discussion right here. I agree that a very high density of logical interfaces is the requirement for an ISP "edge" rather than "core" router. The aggregation to these interface may very well be in what variously is called the access or collection tier. While there's no industry consensus on terminology for the hierarchy associated with ISPs, Cisco has been getting away from core/distribution/access in some of its carrier-oriented presentation. The newer usages seem to be: snipped redefinition of network hierarchy I will be co-organizing a session this June at the Internet Society meeting in Stockholm, along with Lyman Chapin of Verizon/GTE/BBN (chair) and Sue Hares of NextHop. One of our goals is to present multivendor views of what constitutes the edge. There's certainly no consensus, and I haven't begun to discuss content routing here. Howard, thank you for defining some new terminology. I always feel that certain words can help me understand something better ; In terms of understanding this big picture, I have been coming to terms with new designs for edge networks and trying to fit all these concepts together. Content networking is the big one that seems to break a lot of the mold of networking (as I know it, at least) that we've come to rely on over the years. So I deeply understand the need for consensus. Sounds like Stockholm will be ground-shaking ; Absolute agreement that we need a term. Some people call these core routers "because they are part of the Internet core," but it's really stretching it to say that the Internet has a distinct core. Can you get along with the idea that an ISP core router has lots of bandwidth, perhaps lots of MPLS paths, perhaps a big _forwarding_ table (as distinct from routing table), but not much filtering or policy controls? Limited traffic conditioning? Also, all its interfaces tend to be the same general speed. Core networks (as you describe them here) are definitely changing. I am having a hard time with the idea of Carrier's Carrier networks, and some of the other challenging concepts with core networking. I always thought of the Core as where IBGP lives, not "passed over", as in transport. It sounds like your concept of a core here is an IGP carrying infrastructure addresses and maybe "a bunch of LSRs". If this were ATM overlay and not MPLS, would it still be called the same thing? What if it's Optical? What if it's MP(Lambda)S? So, yes, "Internet core" as in carrying Internet (or ISP customer) prefixes. But, no, not "Internet core" as in exchanging prefixes with other AS's (although I'm sure IBGP mesh, route-reflection, and confederations complicate the idea even further -- but at least these terms are currently well understood and defined). Hrmn... how about "BGP Core" and "Core Transmission"? These are words taken from Cisco. BGP Core could define IBGP carrying Internet/customer prefixes across/into/throughout the ISP backbone. Core Transmission could define the MPLS-TE and/or MPLS VPN architecture (LSRs and P-routers) and the underlying transport (could be IP+ATM, could be Optical, etc). In contrast, an ISP edge router has lots of logical interfaces, extensive filtering, policy, and traffic
Re: The Internet core router
"dre" [EMAIL PROTECTED] commented, ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001905b6d4554abd7f@[63.216.127.100]... Depending on the design of the core, the routers at the edge of the core will use full routes to set up MPLS LSPs from one side of the core to the other, but routers internal to the core may not need it if they are under LDP or RSVP-TE control from the edge routers. If you think of the core as interconnecting the POP/access and server sites inside an ISP or an enterprise, there's a good deal of interest in subsecond reconvergence times. This probably is achievable with link state IGPs, using millisecond or microsecond hellos (or relying on hardware failure detection on optical links), and more advanced algorithms than the 40-year-old Dijkstra. In the short to moderate term, there is no foreseeable way to get convergence times this fast with exterior routing. Actually, superfast convergence in the global Internet may be a Really Bad Idea with respect to Internet stability. I don't think I've seen POP/access or server sites that are implementing subsecond reconvergence (especially on the collocation side) with even IGPs at this point. The technology isn't there yet. Without getting into NDA issues, I have gotten customer RFPs that are interested in it, but it's certainly not a requirement yet. There may be less ambitious approaches than full IGP reconvergence in milliseconds, along the lines of precomputing backup routes. MPLS has some fast failover concepts. Combining this with some of the other concepts you brought up is very key. To add another one into the mix, try to solve the problem of stateful failover using "n to many" clustering/high-availability for servers in these environments. Yes. One of the nastiest ones is keeping crypto sync in this sort of environment. Some people want instantaneous IPsec failover, which I tend to regard as insane, incredibly resource-intensive, possibly opening up security holes, etc. Resyncing a session key is more within the range of the realistic. There's a huge issue of deciding what is good enough. In the fault tolerance chapter of my WAN Survival Guide, I quote some of the specifications for a Minuteman ICBM launch control capsule and its communications (i.e., basically keep working through a nuclear attack where you aren't directly hit), and then pose the question -- does your fault tolerance budget match this one? Bringing this to the network layers becomes difficult when considering multiple paths and convergence, be it long-haul, metro, or even across logical local areas (VLANs) at the lower network layers, or external or internal routing at the higher network layers (IGP, MPLS-TE, Content routing, Content switching, etc). This is a huge discussion right here. I agree that a very high density of logical interfaces is the requirement for an ISP "edge" rather than "core" router. The aggregation to these interface may very well be in what variously is called the access or collection tier. While there's no industry consensus on terminology for the hierarchy associated with ISPs, Cisco has been getting away from core/distribution/access in some of its carrier-oriented presentation. The newer usages seem to be: snipped redefinition of network hierarchy I will be co-organizing a session this June at the Internet Society meeting in Stockholm, along with Lyman Chapin of Verizon/GTE/BBN (chair) and Sue Hares of NextHop. One of our goals is to present multivendor views of what constitutes the edge. There's certainly no consensus, and I haven't begun to discuss content routing here. Howard, thank you for defining some new terminology. I always feel that certain words can help me understand something better ; In terms of understanding this big picture, I have been coming to terms with new designs for edge networks and trying to fit all these concepts together. Content networking is the big one that seems to break a lot of the mold of networking (as I know it, at least) that we've come to rely on over the years. So I deeply understand the need for consensus. Sounds like Stockholm will be ground-shaking ; Well, content routing is part of the Stockholm presentation. Not sure who is going to try to bell that cat. There's quite a bit of academic research there as well as product evolution. Don't know if Dmitri Krioukov is still reading this list, but he's far more of an expert on content routing than I am. Absolute agreement that we need a term. Some people call these core routers "because they are part of the Internet core," but it's really stretching it to say that the Internet has a distinct core. Can you get along with the idea that an ISP core router has lots of bandwidth, perhaps lots of MPLS paths, perhaps a big _forwarding_ table (as distinct from routing table), but not much filtering or policy controls?
Re: The Internet core router
lol.anyone know if there is a Juniper cert out there?!?! sipitung wrote: Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The Internet core router
Hi, please have a look this site http://www.lightreading.com/testing/ Have you any comment about this ? Let's us know your opinion. Thanx Si Pitung Just started looking at it tonight. I will be speaking with its author at the IETF meeting next week. I would think long and hard before I'd claim any router is the "best" core router. Individual numbers can be misleading. I have a draft out on single-router BGP convergence time, http://www.isi.edu/internet-drafts/draft-berkowitz-bgpcon-00.txt. It is fairly rough, but starts talking about the interactions of multiple parameters. Unfortunately, the appendix giving various ISP applications for BGP routers isn't in that draft, but will be in the next one. It's misleading to think that all ISP routers need to be "core." Arguably, the highest-bandwidth "core" routers inside an ISP may not need to run full BGP, but have more stringent demands on OSPF, ISIS, and/or MPLS. Think of RFC 2547 "P" routers. An ISP POP access router might have the greatest number of BGP routes and paths, but not as much bandwidth requirements. If the POP router primarily deals with customers, it will advertise only default and partial routes to many of them. Only a small proportion of customers want full routes. A POP router will also generally accept only a small number of routes from customers. Interprovider routers at tier 1 are unlikely to need to exchange full routes Such routers are bandwidth-intense, but the definition of a tier 1 is that you exchange only customer routes (perhaps oversimplifying, but that's close) with other tier 1 providers. A revised draft will be presented at the IETF next week to the benchmarking methodology (BMWG) and inter-domain routing (IDR, responsible for BGP). This draft is coauthored by Alvaro Retana at Cisco, and Sue Hares and Padma Krishnaswamy at NextHop (the former GateD organization, which is the base for quite a number of implementations). Hopefully, we will also get a Juniper coauthor. The plan is that it will become a BMWG working group document in the standards track (well, as much as standards track applies to performance measurement documents, a subtlety of the IETF process). -- "What Problem are you trying to solve?" ***send Cisco questions to the list, so all can benefit -- not directly to me*** Howard C. Berkowitz [EMAIL PROTECTED] Technical Director, CertificationZone.com Senior Mgr. IP Protocols Algorithms, Advanced Technology Investments, NortelNetworks (for ID only) but Cisco stockholder! "retired" Certified Cisco Systems Instructor (CID) #93005 _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
