Was just checking in at the Nortelpress website to see what was new and it appears that Nortel are partnering with Cisco on their certification track, where if you have a CCNA, CCDA or CCDP this counts as a credit towards the Nortel NCDS or NCSS in ERS product sets i.e. passport 8600 etc
You only need to pass one exam on top of your CCNA/DA/DP and you're certified as NCSS! Not quite sure how this works, you must have to validate your Cisco cert on the Nortel cert manager site surely!
I work with ERS every day so this may just have swayed my immediate study plans.
Interesting development
http://www.nortel.com/corporate/news/publications/nortel_press/ers_solutions.html