Central Site Remote Access Switch 291
C
ONFIGURING
A
DVANCED
IP R
OUTING
IP Filters
IP A
DDRESS
P
OOL
B
ACKGROUND
I
NFORMATION
The IP Address Pool feature allows you to configure a list of IP addresses that can be dynamically
assigned to remote IP devices as they connect to the system. This would occur if a remote IP device
calls in to the system and has no IP address, and requests to have one assigned. With this capability,
you no longer need to assign permanent IP addresses to all possible remote IP devices, but rather
only as many IP addresses as the number of possible ISDN connections. If multiple connections are
used, you would not need as many IP addresses as the number of possible ISDN connections. This
can result in a reduction of the number of IP addresses required for remote IP devices.
When a PPP connection is established to the system, the system and the remote device exchange
their IP addresses during the IPCP (IP Control Protocol) phase. If the remote device does not know
its own IP address, the system will assign a proper IP address to it. A proper IP address can be a
permanent IP address configured for the remote device in the device table, or it can be one of the
IP addresses configured in the IP Address Pool. If an IP address from the address pool is used, it
will be returned to the pool when the connection is terminated. This allows the IP address to be
reused for other remote IP devices. As many as 64 IP addresses can be configured in the IP Address
Pool.
Notes: Dynamic IP address assignment from the IP Address Pool is only supported via PPP IPCP.
An IP address should not be configured for the device (either in the on-node device
database or in a remote authentication database) if an IP address is to be assigned to the
device from the IP address pool.
IP F
ILTERS
The IP Filter Configuration is a three-part process. It involves:
1.
configuring packet types
2.
configuring the filters to act on these packet types
3.
applying the filters to selected points in the IP packet processing path
We suggest you become familiar with the IP Filtering mechanism before attempting a
configuration. Refer to
IP Filters Background Information
.
Understandably, when IP Filters are enabled, system performance will slow down. This is due to
the fact that every IP packet will experience a delay while the system is searching for a filter match.
System performance will also be affected by the number of packets, conditions and filters
configured. Refer to the
Limitations
section for details.
