Preparation Of Lab Set Up For Service Provider

I am now focused on prep for the SP lab. This has meant going back to start with theory on certain topics.

I am still using dynamips for study but decided to combine it with some real switches, I already owned two 3550’s and needed a way to link these to my workstation. First I bought some usb nics but after discovering they all had the same mac address…..AND didn’t provide any support for jumbo frames I changed that idea to the use of a third party switch. So off I went in search of a non-cisco reasonable priced switch that could do QinQ. I ended up finding an Extreme Alpine 3804 on Ebay that had 20 x Gig Copper and 64 x 100 Copper ports for the nice sum of 300AUS. The product specs state it supports QinQ so I bought it and jumped in the car for the 3hour journey to pick it up.

The fun began when I got home and attempted to setup my virtual/real combo lab. The general setup is that each virtual router links to the simple Ethernet Switch provided by dynamips. Each port is an access port with a separate vlan id, Ie   R1 Fa0/0 is tagged as VID 101, R1 FA0/1 is tagged as 102,   R2 Fa0/0 is tagged as 201 etc.  The Ethernet switch then has a Trunk link that is bound to a physical Gig nic in my machine which then connects to the newly purchased switch. One advantage of this is that I can use dynamips to capture all traffic on the Gig interface and get to see all the tagging :).

So the issues began when I discovered I have QinQ happening in one direction, Data from the Virtual router to the Virtual switch then to the physical devices was fine, But my newly acquired switch was refusing to do QinQ.  had I bought a dud? After alot! of hair pulling and frustration it turns out that for my Extreme switch to do QinQ, the ingress frame must use a different ethertype than the one that the Extreme switch is using for Dot1q.  So basically if I configured the Switch to use the standard 0×8100 for tagging, No QinQ would occur.

Not a problem I thought and changed the Extreme Switch to use 0×9100. Now from my packet capture I could see both the Extreme switch and Virtual switch performing QinQ except they were now using different ethertypes.. So still not working properly.  Has anyone tried to change the ethertype used by the simple ethernet switch in dynamips? I ended up downloading the source code and checking it out. The source code mentions three types of Dot1q, They were DOT1Q, DOT1Q_2 and DOT1Q_3.     dot1q = 8100, dot1q_2 = 9100 and dot1q_3 = 9200.   I couldn’t workout how to configure the ethernet switch use dot1q_2.  So I changed dot1q = 9100 and recompiled dynamips.

Now everything works perfectly, Simply put my setup is layer2 tunnelling from each virtual router to a port on my physical switches.  Another advantage of this setup is that the gig nic in my workstation and all ports on the Extreme switch support jumbo frames :).

The .net file I am using can be found here

Josh.

Edit: Here a picture of my setup, Sorry about the quality but I had to crawl under my desk. And if anyone picks up on it, I did infact chop up and solder two cisco console cables to make a rs232 to rs232 console cable,.