Cabletron Systems CSX400-DC User Manual
About the CSX400
12 CSX400 and CSX400-DC User’s Guide
The NAT method allows several DHCP clients on a sub network to connect to WAN clients by
allowing the DHCP clients to share a single public IP address. When the CSX400 uses NAT, the
NAT method modifies the IP headers and addresses, and the selected fields in upper layer protocol
headers. This is done to replace the hidden local IP addresses from the sub network with one or
more public InterNic assigned IP addresses that can be sent over the outside network on the
CSX400 WAN interfaces. Once the CSX400 is assigned at least one public IP address, over 250 IP
clients can share this address simultaneously using NAT. This public IP address is assigned
statically by the Internet Service Provider (ISP).
allowing the DHCP clients to share a single public IP address. When the CSX400 uses NAT, the
NAT method modifies the IP headers and addresses, and the selected fields in upper layer protocol
headers. This is done to replace the hidden local IP addresses from the sub network with one or
more public InterNic assigned IP addresses that can be sent over the outside network on the
CSX400 WAN interfaces. Once the CSX400 is assigned at least one public IP address, over 250 IP
clients can share this address simultaneously using NAT. This public IP address is assigned
statically by the Internet Service Provider (ISP).
Point-to-Point Protocol (PPP)
PPP is a data link layer industry standard WAN protocol for transferring multi-protocol data traffic
over point-to-point connections. It is suitable for both high-speed synchronous ports as well as
lower speed asynchronous dial-up ports. With this protocol, options such as security and network
protocols can be negotiated over the connection.
over point-to-point connections. It is suitable for both high-speed synchronous ports as well as
lower speed asynchronous dial-up ports. With this protocol, options such as security and network
protocols can be negotiated over the connection.
This device supports synchronous PPP over the ISDN port. In Single Link Mode, PPP uses one
ISDN B channel for data transmission. PPP runs over each ISDN B channel for two separate
conversations (split B-channel). In Multi-Link Protocol Mode, PPP simultaneously sends and
receives data over two ISDN B-channels on the same connection to optimize bandwidth usage.
ISDN B channel for data transmission. PPP runs over each ISDN B channel for two separate
conversations (split B-channel). In Multi-Link Protocol Mode, PPP simultaneously sends and
receives data over two ISDN B-channels on the same connection to optimize bandwidth usage.
The STAC Electronics Stacker LZS Compression Protocol is supported over PPP providing up to
4:1 data compression.
4:1 data compression.
PAP and CHAP Security
The CSX400 supports the Password Authentication Protocol (PAP) and Challenge Handshake
Authentication Protocol (CHAP) under PPP.
Authentication Protocol (CHAP) under PPP.
PAP provides verification of passwords between devices using a 2-way handshake. One device
(peer) sends the system name and password to the other device (authenticator). Then the
authenticator checks the peer’s password against the configured remote peer’s password and
returns acknowledgment.
(peer) sends the system name and password to the other device (authenticator). Then the
authenticator checks the peer’s password against the configured remote peer’s password and
returns acknowledgment.
CHAP is more secure than PAP as unencrypted passwords are not sent across the network. CHAP
uses a 3-way handshake and supports full or half-duplex operation.
uses a 3-way handshake and supports full or half-duplex operation.