Cisco DPC2434 User Manual page 97

Field
Phase 2 authentication Allows you to select an authentication type for another level of
Phase 2 SA lifetime
4011350 Rev D
Description
security. Select one of the following three authentication types:

MD5

SHA

Null (none)
You may choose any authentication type as long as the other end of the
VPN tunnel uses the same method
Note: SHA is recommended because it is more secure.
Allows you to enter the number of seconds for an individual rotating
key to last until a re-key negotiation between each endpoint occurs.
Smaller lifetimes are generally more secure since it would give a
hacker a smaller amount of time to try to crack the key. However, key
negotiation does take up bandwidth, so network throughput is
sacrificed with small lifetimes. The default setting for Phase 2 is 3,600
seconds.
How Do I Configure the Wireless Home Gateway?
97