Hi! On 09:12 Tue 25 Sep , V.Ravikumar wrote:
On Mon, Sep 24, 2012 at 9:03 PM, <michi1@michaelblizek.twilightparadox.com>wrote:
Hi!
On 17:02 Mon 24 Sep , V.Ravikumar wrote:
Hello all ,
Could some body please suggest any books/links for Linux networking protocol development. Protocol development at L2/L3 layers.
There is a book called "The Linux Networking Architecture: Design and Implementation of Network Protocols in the Linux Kernel".
Is there anything in particular you are looking for?
I need information specifically about VPN technology like MPLS and other related stuff. About their design & implementation at layer L2 level.
MPLS is not really a VPN, but rather a layer 2.5 encapsulation supposed to combine the speed of switching with the flexibility of routing. It should be possible to use MPLS to build VPNs, but I guess few people did this before. Also, MPLS is probably not in widespread use by linux to begin with. There are some "other" VPN technologies as well: - ipsec: This is a standard which is implemented by most "hardware" firewalls and it is quite popular in corporate networks. The linux implementation does not do anything at layer 2 at all. Packet are captured before they are passed to the layer 2 and encapsulated. They pass iptables twice. In practice ipsec can be pretty weird/confusing. - openvpn: cross platform free+open source project; It connects to the other side with either udp or tcp. It creates a virtual network device. Everything you send to this device will be sent to the other side as if the machines were directly connected. On linux openvpn runs completely in userspace and creates the virtual device via the tun/tap interface. If you are interested in how to create such a virtual device in the kernel, you can want to take a look at the ethos project. Its project site seems down/gone, but you can get a copy here: http://michaelblizek.twilightparadox.com/ethos.tar.gz -Michi -- programing a layer 3+4 network protocol for mesh networks see http://michaelblizek.twilightparadox.com