Re: AS numbers - Is there a global crisis?
I was totally involved two years ago in setting up a BGP peering with both UUNET and Sprint at the same time for an ISP. At that time I remember very well that they accept anything less than /19. Today I'm dealing now with Teleglobe and also they accept blocks less than that. When we talk about ISP peering with Carriers especially more than one, the ISP sometimes needs to advertise some of his /19 blocks to one and rest to another. - Original Message - From: "Thanatos" [EMAIL PROTECTED] To: "J Roysdon" [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Sunday, January 21, 2001 11:03 PM Subject: Re: AS numbers - Is there a global crisis? I could not give you exact information, when I have looked at peering policies in the past it normally depends on the type of address space involved. If the addresses came from what was typically a Class C space they may not require a large aggregation of IP addresses. It is pretty much standard that coming from what was typical Class A space that anything smaller than a /19 would not be advertised or accepted. I know of a broadband cable ISP that ran into this aggregation problem with Verio. None of their users could reach anything within Verio's network (Or ATT for that matter) The following link has an example of Verio's peering policy, which I am assuming is pretty standard as peering policies go. http://info.us.bb.verio.net/routing.html#PeerFilter -- Kevin. "J Roysdon" [EMAIL PROTECTED] wrote in message 94gm53$u1$[EMAIL PROTECTED]">news:94gm53$u1$[EMAIL PROTECTED]... I've heard that most ISPs will filter less than /19. If this is true, then only the ISP who owns the aggregate route will get heard by most other ISPs. Can anyone confirm at which point most ISPs filter? I know at a minimum most won't accept more specific than /24. I finally got some evil internal routing vpn issues taken care of, and should be finally implementing BGP with Sprint UUNET (geeze, it's been forever dealing with these internal issues). If nothing else, I'll ask their BGP folks what they filter at. I can also confirm that about double the ASN's in use (9731) have been handed out. We were given ASN 18506 in September. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ Cisco resources: http://r2cisco.artoo.net/ ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001919b68e6e6b973a@[63.216.127.98]... Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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 subscripti
Re: AS numbers - Is there a global crisis?
I've heard that most ISPs will filter less than /19. If this is true, then only the ISP who owns the aggregate route will get heard by most other ISPs. Can anyone confirm at which point most ISPs filter? I know at a minimum most won't accept more specific than /24. I finally got some evil internal routing vpn issues taken care of, and should be finally implementing BGP with Sprint UUNET (geeze, it's been forever dealing with these internal issues). If nothing else, I'll ask their BGP folks what they filter at. I can also confirm that about double the ASN's in use (9731) have been handed out. We were given ASN 18506 in September. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ Cisco resources: http://r2cisco.artoo.net/ ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001919b68e6e6b973a@[63.216.127.98]... Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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: AS numbers - Is there a global crisis?
I could not give you exact information, when I have looked at peering policies in the past it normally depends on the type of address space involved. If the addresses came from what was typically a Class C space they may not require a large aggregation of IP addresses. It is pretty much standard that coming from what was typical Class A space that anything smaller than a /19 would not be advertised or accepted. I know of a broadband cable ISP that ran into this aggregation problem with Verio. None of their users could reach anything within Verio's network (Or ATT for that matter) The following link has an example of Verio's peering policy, which I am assuming is pretty standard as peering policies go. http://info.us.bb.verio.net/routing.html#PeerFilter -- Kevin. "J Roysdon" [EMAIL PROTECTED] wrote in message 94gm53$u1$[EMAIL PROTECTED]">news:94gm53$u1$[EMAIL PROTECTED]... I've heard that most ISPs will filter less than /19. If this is true, then only the ISP who owns the aggregate route will get heard by most other ISPs. Can anyone confirm at which point most ISPs filter? I know at a minimum most won't accept more specific than /24. I finally got some evil internal routing vpn issues taken care of, and should be finally implementing BGP with Sprint UUNET (geeze, it's been forever dealing with these internal issues). If nothing else, I'll ask their BGP folks what they filter at. I can also confirm that about double the ASN's in use (9731) have been handed out. We were given ASN 18506 in September. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ Cisco resources: http://r2cisco.artoo.net/ ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001919b68e6e6b973a@[63.216.127.98]... Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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: AS numbers - Is there a global crisis?
I could not give you exact information, when I have looked at peering policies in the past it normally depends on the type of address space involved. If the addresses came from what was typically a Class C space they may not require a large aggregation of IP addresses. It is pretty much standard that coming from what was typical Class A space that anything smaller than a /19 would not be advertised or accepted. I know of a broadband cable ISP that ran into this aggregation problem with Verio. None of their users could reach anything within Verio's network (Or ATT for that matter) The following link has an example of Verio's peering policy, which I am assuming is pretty standard as peering policies go. http://info.us.bb.verio.net/routing.html#PeerFilter -- Kevin. "J Roysdon" [EMAIL PROTECTED] wrote in message 94gm53$u1$[EMAIL PROTECTED]">news:94gm53$u1$[EMAIL PROTECTED]... I've heard that most ISPs will filter less than /19. If this is true, then only the ISP who owns the aggregate route will get heard by most other ISPs. Can anyone confirm at which point most ISPs filter? I know at a minimum most won't accept more specific than /24. I finally got some evil internal routing vpn issues taken care of, and should be finally implementing BGP with Sprint UUNET (geeze, it's been forever dealing with these internal issues). If nothing else, I'll ask their BGP folks what they filter at. I can also confirm that about double the ASN's in use (9731) have been handed out. We were given ASN 18506 in September. -- Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+ List email: [EMAIL PROTECTED] Homepage: http://jason.artoo.net/ Cisco resources: http://r2cisco.artoo.net/ ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001919b68e6e6b973a@[63.216.127.98]... Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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]
AS numbers - Is there a global crisis?
I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
I wouldn't think that's t much of an issue. As far as I understand it, you only get assigned a public AS number if you're a m_a_j_o_r provider--like PSInet, ATT, MCI, etc... If you're a mid-sized to smaller organization, you probably can get by using a private AS from a larger provider. Can s/body confirm this? --- "Fowler, Joey" [EMAIL PROTECTED] wrote: I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] = Don't forget to cross your digits... Dan West -- CCNA, CCNP (in progress) __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
To get an ASN you have to show that you either have a unique routing policy or that you are multihomed to separate providers. Sure, there are lots of companies that have multiple internet connections, but how many *really* need to have redundant connections to separate ISPs? Not really that many, since there are other ways to achieve redundancy. Now, with that said, we applied for and received an ASN a couple of months ago and they have already issued over 300 since then. At that rate, it won't be too long before we run into trouble. John I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
since there are other ways to achieve redundancy. Please advise what "other ways" there are to achieve redundancy for 'inbound' traffic via the Internet. Brian --- John Neiberger [EMAIL PROTECTED] wrote: To get an ASN you have to show that you either have a unique routing policy or that you are multihomed to separate providers. Sure, there are lots of companies that have multiple internet connections, but how many *really* need to have redundant connections to separate ISPs? Not really that many, since there are other ways to achieve redundancy. Now, with that said, we applied for and received an ASN a couple of months ago and they have already issued over 300 since then. At that rate, it won't be too long before we run into trouble. John I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
Inbound is a little more difficult than outbound, but I believe you can work with your ISP to accomplish this. You could have redundant connections to a single ISP if you were using address space assigned from them only. You really wouldn't even need BGP for this, but if you wanted to use it you could then use a private ASN. Since you only have one ISP, it's not necessary to advertise your specific subnet; the aggregate advertised by the ISP would suffice. The specific strategy used depends on how paranoid you are. If you think it's a realistic possibility that your entire ISP might fail, then it's a good idea to get a connection to a different ISP and run BGP. However, I think many companies would be safe with redundant connections to the same ISP, yet to different locations. I may be wrong about this, but the above is correct as far as I understand it. I'm pretty new to this, so I hope someone with more experience than I responds to this thread. John since there are other ways to achieve redundancy. Please advise what "other ways" there are to achieve redundancy for 'inbound' traffic via the Internet. Brian --- John Neiberger [EMAIL PROTECTED] wrote: To get an ASN you have to show that you either have a unique routing policy or that you are multihomed to separate providers. Sure, there are lots of companies that have multiple internet connections, but how many *really* need to have redundant connections to separate ISPs? Not really that many, since there are other ways to achieve redundancy. Now, with that said, we applied for and received an ASN a couple of months ago and they have already issued over 300 since then. At that rate, it won't be too long before we run into trouble. John I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). Feel free and give me a call if you'd like to discuss further. -Brad Ellis CCIE#5796 Cisco Hardware: www.optsys.net 248-293-0091 [EMAIL PROTECTED] "Brian Wilcox" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... since there are other ways to achieve redundancy. Please advise what "other ways" there are to achieve redundancy for 'inbound' traffic via the Internet. Brian --- John Neiberger [EMAIL PROTECTED] wrote: To get an ASN you have to show that you either have a unique routing policy or that you are multihomed to separate providers. Sure, there are lots of companies that have multiple internet connections, but how many *really* need to have redundant connections to separate ISPs? Not really that many, since there are other ways to achieve redundancy. Now, with that said, we applied for and received an ASN a couple of months ago and they have already issued over 300 since then. At that rate, it won't be too long before we run into trouble. John I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler We are told that talent creates its own opportunities. But it sometimes seems that intense desire creates not only its own opportunities, but its own talents. - Eric Hoffer (1902-1983 American Author Philosopher) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] __ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.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: AS numbers - Is there a global crisis?
If there is a global crisis would it not be cataloged here? http://www.telstra.net/ops/bgptable.html Subject: Re: AS numbers - Is there a global crisis? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
I've been studying BGP, but something that keeps bothering me when I study it is that there are less than 65000 , (64511 to be exact) public AS numbers. It would seem to me that these would quickly run as out, as I would think that there are that many corporations world-wide that connected to the internet via BGP. Any thoughts on this? Thanks, Joey Fowler A valid observation that AS numbers are not an unlimited resource. The idea of a 32-bit number is indeed being examined in the IETF. In general, it isn't an immediate crisis. As of today's CIDR Report from Tony bates, there are 9674 AS in the global routing system. IIRC from September or so, there were then about twice this number that actually had been issued. For enterprise multihoming when the enterprise homes to multiple POPs of the same upstream, private AS work quite well. When enterprises multihome to two upstreams, private AS still can work with more administrative coordination. The bottom line is that the number of prefixes in the table is a more serious problem at the moment. This is more a convergence and computation problem than a memory problem. No question, however, that the 16 bit AS space won't last forever. Based on current projections, though, the IPv4 address space is likely to exhaust first. IPv6 is starting to become real; the 3rd generation wireless industry has adopted it and that is likely to be the "killer application" for V6. -- "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, 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]
Re: AS numbers - Is there a global crisis?
Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: AS numbers - Is there a global crisis?
By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 CL: And two more routes go into the global tables. Wasn't CIDR supposed to stop this kind of thing? ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Howard C. Berkowitz Sent: Friday, January 19, 2001 2:28 PM To: [EMAIL PROTECTED] Subject:Re: AS numbers - Is there a global crisis? Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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: AS numbers - Is there a global crisis?
By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 CL: And two more routes go into the global tables. Wasn't CIDR supposed to stop this kind of thing? ;- Correct. But BGP and CIDR were not designed to optimize traffic flow. This is a way to coerce them into doing it. The significant thing about a dog walking on its hind legs is not how well he does it, but that he does it at all. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: AS numbers - Is there a global crisis?
Very true, thanks Howard, I left that out. -B ""Howard C. Berkowitz"" [EMAIL PROTECTED] wrote in message news:p05001919b68e6e6b973a@[63.216.127.98]... Brian, Hi! Funny you bring this up, I just got a phone call on it today. Basically, you can have two seperate ISPs and have incoming redundant connections without using BGP. ISP1 will provide a block of IPs from a portion of their CIDR block to the "company." Since this is part of ISP1s CIDR block, they already broadcast a route to the rest of the internet containing the company's block of IPs. ISP2 will then also broadcast a route to ISP1's block of IPs (just the block!!!). The tricky part comes when you try to do load balancing between the two for incoming traffic!!! I am making several assumptions here (that the ISPs will play nice with each other among other things). ISP1, however, MUST advertise not its aggregate alone, but both its aggregate and the more-specific customer block that also is advertised by ISP2. Assume the following: ISP1 has the block 192.168.0.0/16. This is the only block it advertises. It delegates 192.168.2.0/24 to the customer. ISP2 advertises 192.168.2.0/24. So in the global routing table, there will be two routes: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP2 Since 192.16.2.0/24 is more specific than 192.168.0.0/16, the rest of the world will send ALL 192.168.2.0/24 traffic to ISP2. By having ISP1 advertise both its aggregate and the more-specific, the routing system conceptually will contain: 192.168.0.0/16 ISP1 192.168.2.0/24 ISP1 192.168.2.0/24 ISP2 Other AS will install the ISP1 route to 192.168.2.0/24 if their connectivity to ISP1 is better than their connectivity to ISP2, and vice versa. _ 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]
