Thank you all for the replies To be honest I was leaning towards the subinterfaces alternative for implementing L3 termination points for DHCP subscribers.
Just to sum things up: Subinterfaces alternative: -They comsume an internal VLAN for each subintreface. -For each subsciber no mac-address table is required, just and ARP entry. EVC alternative: -Using a bridge domain only one VLAN will suffice. -But because of the bridge-domain the 7600 will have to populate its mac-address table with one entry for each subscriber. -Also since the evc-alternative is "partly L2 based" the dhcp-snooping security mechanisms can be employed. I am concerned about the mac-address capacity. Since servicing DHCP subscribers in ES+ is purely a L3 service there should be no need to populate the mac-table with extra entries (in this way more resources can be used for other L2 services). Victor >On Sat, Oct 24, 2009 at 5:19 PM, Arie Vayner (avayner) <[email protected]> >wrote: > Victor, > > Use the EVC alternative. > It would allow you to get the flexibility offered by EVC with regards to > VLAN number space, L2 services scalability, QOS and many other advanced > capabilities. > > Arie > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Victor Lyapunov > Sent: Tuesday, October 20, 2009 09:54 > To: [email protected] > Subject: [c-nsp] 7609 DHCP alternatives - EVC / Subinterfaces > > Hi All > > I am trying to test DHCP functionality with 7600 router. Traffic > arrives from all customer facing interfaces (ES+), arrive using the > same VLAN. 7600 perfoms DHCP relay and acts as a gateway for all of > them. With the new cards ES+ we have two options for the configuration > of customer facing interfaces > > 1. Using EVC + SVI interface > > int g4/1 > service instance 100 ethernet > encapsulation dot1q 100 > rewrite ingress tag pop 1 symmetric > bridge-domain 100 split-horizon > int g4/2 > service instance 100 ethernet > encapsulation dot1q 100 > rewrite ingress tag pop 1 symmetric > bridge-domain 100 split-horizon > > int Vlan 100 > ip address 10.0.0.1 255.255.255.0 > ip helper address 192.168.0.1 > > 2. Using IP subinterfaces > > int loopback 100 > ip address 10.0.0.1 255.255.255.0 > > int g4/1.100 > encapsulation dot1q 100 > ip address unnumbered loopback 100 > ip helper address 192.168.0.1 > > int g4/2.100 > encapsulation dot1q 100 > ip address unnumbered loopback 100 > ip helper address 192.168.0.1 > > > Both configurations seem to achieve the same effect but I am not sure > which one > is the preferable for large amount of traffic / subscribers. > > For example due to the bridge domain I would expect that the first > alternative will > create more entries in the mac-address table. > > Thanx > > Victor > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
