Large packets sometimes dropped by routers
If DF=0, may still be dropped
If DF=1, MIP suffers from ICMP black holes
Realistic deployment issue
E.g. one ADSL box silently drops packets > 1360 (if DF=0)
RRQ/RRP goes through but some traffic is blackholed!
RFC 3519 => fragment before encapsulation, avoids fragments (good), but what is a good MTU?
Some implementations have built-in restrictions like 1300 octets => no configurability for administrator
This issue could be avoided by (a) robust discovery of MTU, or (b) configurable, negotiated MTU