I've seen topics like this posted on this forum before, but I think it's worth a reminder. Nortel/Avaya has really made an effort with documentation and best practices with its equipment. For any of you that have suddenly been put in charge of Nortel/Avaya ERS equipment or have chosen it as its network equipment please utilize this documentation. For someone like me, before this documentation or forums like this I felt I was on an island when it was time to make network design decisions.
On nortel.com you can find the Small, Medium and Large Campus based pdf documents. It is very much worth a look at.
NN48500-575_1.0_Large_Campus_TSG
NN48500-574_1.0_Medium_Campus_TSG
NN48500-573_1.0_Small_Campus_TSG.pdf
I think with the combination of great forums like this and Nortel/Avaya continued improvements with documentation any network admin with some motivation can manage a stable/well designed Nortel/Avaya network.
Regards,
Todd