Using CE Router for Internet and VPN services
Hi, can someone explain me why service providers (Internet and/or L3 VPN services) obligate customers to use CE routers. Why they cannot configure more than /30 (in some cases /31) subnet mask on PE interface side for me? In that case I can use cheap L2 switch and use default gateway on all my PCs in the LAN, pointing to SP PE. Please describe all benefits and detriments of using more than /30 subnet on SP PE. Some good links will be very useful for me. TIA! -- AA
Hello Akhmedd Aly wrote:
can someone explain me why service providers (Internet and/or L3 VPN services) obligate customers to use CE routers. Why they cannot configure more than /30 (in some cases /31) subnet mask on PE interface side for me? In that case I can use cheap L2 switch and use default gateway on all my PCs in the LAN, pointing to SP PE.
Managed services. The concept of "the demarcation point is an Ethernet port" is an important selling point for some people, especially when IT staff are not on-site. Another major downside is the WAN circuit type - Ethernet circuits typically don't mirror the link state correctly. Furthermore, troubleshooting is easier for the SP if it's their kit at both ends of the circuit. With this kind of technology, anything is usually possible, but restricted by the practices of the SP or their superior knowledge given that they have hundreds, maybe thousands of customers and therefore a lot more experience than many of their customers.
Please describe all benefits and detriments of using more than /30 subnet on SP PE. Some good links will be very useful for me.
We have /29s on our PE-to-CE links. This allows for the Ethernet-presented WAN circuit to come in to a Layer 2 switch at either end, and two CE and two PE routers run eBGP in a full mesh. The benefits of this aren't obvious until you do the same for a backup link via another PoP - re-use the same CE routers, but full-mesh to the other PoP site. Result - you can lose a CE router but not have to fail over to the backup PoP. Peter
Akhmedd Aly wrote:
Please describe all benefits and detriments of using more than /30 subnet on SP PE. Some good links will be very useful for me.
Don't know all, but have you see the arp tables on a PE router? Have you seen some of the crazy things devices other than routers can do on ethernet? There are many advantages to CE routers. SP controlled CEs take it even further in managing demarcation, other services, and offloading of any service level restrictions to the CE. Also, I believe on ethernet, some SPs do layer 2 level security and filtering which is made easier when only 1 MAC per CE. Jack
Please describe all benefits and detriments of using more than /30 subnet on SP PE. Some good links will be very useful for me.
Don't know all, but have you see the arp tables on a PE router? Have you seen some of the crazy things devices other than routers can do on ethernet?
Good point. We allow VPN users to have up to a /29 directly connected. Any more than that and we require a CE router. Important for scaling when you have PEs aggregating 10k or 20k customer interfaces. Steinar Haug, Nethelp consulting, sthaug@nethelp.no
participants (4)
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Akhmedd Aly -
Jack Bates -
Peter Hicks -
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