From SIPfoundry sipx, The Open Source SIP PBX for Linux - Calivia

[edit] kernel-ib causing an unresolvable chain of dependencies

When you run up2date --update, particularly if haven't run it in a very long time you might be this response

Unresolvable chain of dependencies:
libibverbs  1.0.3-1                      requires kernel-ib
libmthca  1.0.2-1                        requires kernel-ib
libsdp  0.9.0-1                          requires

Redhat has noted solution here

http://kbase.redhat.com/faq/FAQ_58_8726.shtm

You can either clear item 20 which will allow your system to update it's kernel, or add all the items from the above link and continue to skip kernel upgrades.