Cisco DPC3827 User Manual page 42

How Do I Configure My DOCSIS Residential Gateway?
Section
42
Field Description
Select one of the following options for the key exchange method:

Auto (IKE)
– Encryption: The Encryption method determines the length of
the key used to encrypt/decrypt ESP packets. Notice that
both sides must use the same method.
– Authentication: The Authentication method authenticates
the Encapsulating Security Payload (ESP) packets. Select
MD5 or SHA. Notice that both sides (VPN endpoints) must
use the same method.
MD5: A one-way hashing algorithm that produces a

128-bit digest
 SHA: A one-way hashing algorithm that produces a
160-bit digest
– Perfect Forward Secrecy (PFS): If PFS is enabled, IKE Phase
2 negotiation will generate new key material for IP traffic
encryption and authentication. Note that both sides must
have PFS enabled.
– Pre-Shared Key: IKE uses the Pre-Shared Key to authenticate
the remote IKE peer. Both character and hexadecimal values
are acceptable in this field, e.g., "My_@123" or
"0x4d795f40313233". Note that both sides must use the same
Pre-Shared Key.
– Key Lifetime: This field specifies the lifetime of the IKE
generated key. If the time expires, a new key will be
renegotiated automatically. The Key Lifetime may range
from 300 to 100,000,000 seconds. The default lifetime is 3600
seconds.
4025083 Rev A