Cabletron Systems CyberSWITCH CSX101, User'S Information Manual

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About the CyberSWITCH 100 Router
16 CyberSWITCH 100 Advanced User Information
Local and Remote WAN IP Addresses —
You may need to specify a Local WAN IP address
and/or a Remote WAN IP address for the WAN connection to the remote router depending on IP
address negotiation under PPP. Check with your system administrator for details on whether the
router must communicate in numbered or unnumbered mode and what addresses are required.
In unnumbered mode, neither IP address is defined on the link. In numbered mode, one IP address
is defined on each end of the WAN link. The CyberSWITCH 100 automatically determines
whether to run in unnumbered mode or numbered mode. If unnumbered mode negotiation fails,
numbered mode is attempted using the Ethernet LAN IP address as a default. If you have specified
a Local WAN IP address, unnumbered mode negotiation is not performed; i.e., the operating mode
is numbered. If a Local WAN IP address is explicitly defined, the router will not, as a rule, accept
another local address from the remote end. In numbered mode without an explicit Local WAN IP
address, this address can be negotiated to a different value by the remote end. If the remote router
supports unnumbered mode, neither address needs to be specified. Figure 3, below, is a simple
example of an unnumbered mode configuration.
Figure 3 CSX100 in Unnumbered Mode Addressing
For numbered mode, consider the capabilities of the remote router as well as your requirements.
Specify a Local WAN IP address if the CyberSWITCH 100 must be on the same subnetwork as the
remote router.Figure 7, below, is an example of a Class B IP network (128.1).
Figure 4 CSX100 in Numbered Mode Addressing
UNNUMBERED MODE
CyberSWITCH 100
WAN LINK
NO SOURCE
IP ADDRESS
NO REMOTE
IP ADDRESS
REMOTE ROUTER
100_1
1
NUMBERED MODE
SAME SUBNETWORK AS REMOTE
CyberSWITCH 100
WAN LINK
128.1.129.1
255.255.255.0 128.1.1.2
255.255.255.0
REMOTE ROUTER
*SOURCE IP
ADDRESS
*SPECIFY SOURCE IP ADDRESS IF IT MUST BE ON SAME SUBNETWORK AS THE REMOTE ROUTER.