Hello, In reading the IOS Essentials for ISP's PDF, ver 2.84 http://www.cisco.com/public/cons/isp/documents/IOSEssentialsPDF.zip i came across something I believe might need a little bit of clarification. I dont know if many ISP's use this method or not, but i find it particularly usefull. On page 29, under the Caveats section, specifically the routing protocols part, it is stated that : ". Routing Protocols. If a routing protocol needs to be run over this link, it is operationally much easier to use IP addresses. Don't use "ip unnumbered" if the customer is peering with you using BGP across the link, or if the link is an internal backbone link. Simply use a network with a /30 address mask. (Routing will work over unnumbered links but the extra management and operational complexity probably outweighs the small address space advantage gained.) " Using Ip unnumbered and BGP is something that works extremely well, in the following case. The wan interface is unnumbered to the ethernet interface. The ethernet interface is using a primary IP that is the one that should be configured on the WAN interface, and a secondary IP that is the LAN IP In most cases, the Provider will want to peer its BGP session to the IP it assigned the customer. This setup allows the BGP session to be peered to the Ethernet interface, which in turns leeds to an end to end point of failure, from the Ethernet Interface, to the Wan Interface. This succesfully allows the ISP to monitor the customer's network availability without the use of piningin methods, and relying solely upon the well being of the BGP session. If this message is off list topic, i apologize for the inconvenience. Morgan Dollard Disclaimer ---------- This email and any files transmitted with it are confidential and are intended solely for the use of the individual or entity to whom they are addressed. This communication represents the originator's personal views and opinions, which do not necessarily reflect those of the NSC Group. If you are not the original recipient or the person responsible for delivering the email to the intended recipient, be advised that you have received this email in error, and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. If you received this email in error, please immediately notify administrator@nscglobal.com.
At Mon, 4 Sep 2000, owner-routing-wg@ripe.net wrote:
In most cases, the Provider will want to peer its BGP session to the IP it assigned the customer. This setup allows the BGP session to be peered to the Ethernet interface, which in turns leeds to an end to end point of failure, from the Ethernet Interface, to the Wan Interface. This succesfully allows the ISP to monitor the customer's network availability without the use of piningin methods, and relying solely upon the well being of the BGP session.
But what if the ethernet interface dies? Your BGP session dies with it. For that reason it is advised to assign the BGP peer address to your loopback device and set the peering from that address. Mark Lastdrager Pine Internet -- email: mark@lastdrager.nl :: ML1400-RIPE :: tel. +31-70-3111010 http://www.pine.nl :: RIPE RegID nl.pine :: fax. +31-70-3111011 PGP key ID 92BB81D1 :: Dutch security news @ http://security.nl Today's excuse: Electrons on a bender
Ah yes, creating a NOC alarm every time the caretaker switches the hub off ;-) tb Morgan Dollard wrote:
Hello, In reading the IOS Essentials for ISP's PDF, ver 2.84 http://www.cisco.com/public/cons/isp/documents/IOSEssentialsPDF.zip
i came across something I believe might need a little bit of clarification.
I dont know if many ISP's use this method or not, but i find it particularly usefull.
On page 29, under the Caveats section, specifically the routing protocols part, it is stated that : ". Routing Protocols. If a routing protocol needs to be run over this link, it is operationally much easier to use IP addresses. Don't use "ip unnumbered" if the customer is peering with you using BGP across the link, or if the link is an internal backbone link. Simply use a network with a /30 address mask. (Routing will work over unnumbered links but the extra management and operational complexity probably outweighs the small address space advantage gained.) "
Using Ip unnumbered and BGP is something that works extremely well, in the following case. The wan interface is unnumbered to the ethernet interface. The ethernet interface is using a primary IP that is the one that should be configured on the WAN interface, and a secondary IP that is the LAN IP
In most cases, the Provider will want to peer its BGP session to the IP it assigned the customer. This setup allows the BGP session to be peered to the Ethernet interface, which in turns leeds to an end to end point of failure, from the Ethernet Interface, to the Wan Interface. This succesfully allows the ISP to monitor the customer's network availability without the use of piningin methods, and relying solely upon the well being of the BGP session.
If this message is off list topic, i apologize for the inconvenience.
Morgan Dollard
Disclaimer ---------- This email and any files transmitted with it are confidential and are intended solely for the use of the individual or entity to whom they are addressed. This communication represents the originator's personal views and opinions, which do not necessarily reflect those of the NSC Group. If you are not the original recipient or the person responsible for delivering the email to the intended recipient, be advised that you have received this email in error, and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. If you received this email in error, please immediately notify administrator@nscglobal.com.
On Wed, 6 Sep 2000, Tony Barber wrote:
Ah yes, creating a NOC alarm every time the caretaker switches the hub off ;-)
Even worse, you don't know if it actually is a link problem or "just" an ethernet problem when the link takes a dive into to the deep blue... Use numbered links, or addresses from a loopback if you must use unnumbered links.
tb
Morgan Dollard wrote:
Hello, In reading the IOS Essentials for ISP's PDF, ver 2.84 http://www.cisco.com/public/cons/isp/documents/IOSEssentialsPDF.zip
i came across something I believe might need a little bit of clarification.
I dont know if many ISP's use this method or not, but i find it particularly usefull.
On page 29, under the Caveats section, specifically the routing protocols part, it is stated that : ". Routing Protocols. If a routing protocol needs to be run over this link, it is operationally much easier to use IP addresses. Don't use "ip unnumbered" if the customer is peering with you using BGP across the link, or if the link is an internal backbone link. Simply use a network with a /30 address mask. (Routing will work over unnumbered links but the extra management and operational complexity probably outweighs the small address space advantage gained.) "
Using Ip unnumbered and BGP is something that works extremely well, in the following case. The wan interface is unnumbered to the ethernet interface. The ethernet interface is using a primary IP that is the one that should be configured on the WAN interface, and a secondary IP that is the LAN IP
In most cases, the Provider will want to peer its BGP session to the IP it assigned the customer. This setup allows the BGP session to be peered to the Ethernet interface, which in turns leeds to an end to end point of failure, from the Ethernet Interface, to the Wan Interface. This succesfully allows the ISP to monitor the customer's network availability without the use of piningin methods, and relying solely upon the well being of the BGP session.
If this message is off list topic, i apologize for the inconvenience.
Morgan Dollard
Disclaimer ---------- This email and any files transmitted with it are confidential and are intended solely for the use of the individual or entity to whom they are addressed. This communication represents the originator's personal views and opinions, which do not necessarily reflect those of the NSC Group. If you are not the original recipient or the person responsible for delivering the email to the intended recipient, be advised that you have received this email in error, and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. If you received this email in error, please immediately notify administrator@nscglobal.com.
------------- Elcom ------------- Network Operations Center --------- Jan-Erik Eriksson mailto: jee@alcom.aland.fi Elcom phone: +358 18 23500 PB 233, Torggatan 10 fax: +358 18 14643 FIN-22100 Mariehamn URL: http://www.alcom.aland.fi
participants (4)
-
Jan-Erik Eriksson -
Mark Lastdrager -
Morgan Dollard -
Tony Barber