Thursday, March 24, 2011

Route me

Just spent a couple of days at Alcatel learning how to drive a service router network.  Im going to be managing an ethernet aggregation and transport network based on the Alcatel 7450 ESS-12 and ESS-7 router technology, heres a pic of one of the monsters:

Pretty heavy duty gear 2 terabit backplane, redundant controllers, everything hot swappable, takes 10 line cards with up to 48 10G ethernet ports each.  I nearly died when told the price of the things, each line card is just over $1,000,000 and there are 10 of them in there.  Then youve got to load them with SFPs or XFPs, which depending on the distance you need to go (and whether fibre or copper) go for $1-5,000 each.  I think we need about 1,000 of them all up?  Good job we are not paying retail.

The logical network is a bit complex.... its an OSPF cloud used to support an MPLS switching network.  Over that we then run either RSVP-TE or TLDP to allow us to specifiy layer 2 LSPs, and once youve got those then you can build SDPs and create entry/exit SAPs *Then* you can create VLL e-pipes and bolt them to the SAPs.  Finally, you can physically plug stuff into the VLL physical terminations the SAPs extend to and get yourself a data route.

Now, take at least two of these things (up to 16) and bond them into a ling aggregation group (a LAG) which creates a virtual network interface with multiple layer 2 routes inside it.  To make it a bit more robust, well do multi-chassis LAG.  With MC-LAG the bonded physical interfaces are spread across multiple pieces of equipment, so no one route failure can take you down, and even a complete chassis failure cant.

Now, backhaul all this through an absolute minimum of two geographically diverse and completely redundant DWDM transmission paths.  The most common way of doing this is nested and overlapped transmission rings so youve got both an eastbound and a westbound interface at all times, so if anything fails you just go the other way around the ring, and even then youve got two totally separate rings going 400% protection.

Driving all this is a wee bit daunting, and the management system is... yeah...

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