DM16E1 / DM4E1 Operation and Installation Manual - 204-4001-19
73
9.
ROUTING
Routing is one of the special features included in the main card of DM16E1/DM4E1, and it has two WAN
ports:
•
WAN1: dedicated to the DMLAN protocol.
•
WAN2: PPP or Frame Relay.
It also has a LAN Ethernet port. Each port has a unique IP number, independent from the others.
The LAN interface is of Ethernet 10BaseT type and is made available via the RJ45 connector located at
the rear panel. The interface is the same used for SNMP management in LAN environment, and the panel
is identified as ROUTER/SNMP in order to differentiate it from the RJ45 connector used in Remote Bridge
systems. Pinout allows direct connection to a hub or switch using a cable (Table 13).
WAN1 port flows through the management channel with a standard configuration (40kbit/s). Whenever
possible, the WAN1 uses an E1 channel of 2Mbit/s, improving management performance.
WAN2 port may be any E1 tributary channel within aggregate or local tributary channels (E1 or V.35), and
follows RFCs 1661 and 1662 for PPP, and ITU Q933, Annex A, for Frame Relay. In Frame Relay systems,
WAN2 interfaces always behave as end elements (UNI-User).
As for the operation mode, routing may be classified as follows:
−
Static – starting from routes added via terminal or via SNMP management. A maximum of 10
static routes can be configured in each modem.
−
Dynamic – following protocols RIP V1 and RIP V2 (protocols for learning and activation of routes).
DM16E1/DM4E1 cards are able to translate local IP addresses into one global IP per interface (NATP,
NAT/PAT - network address translation/port address translation).
In DM16E1 and DM4E1 multiplexers, NAT runs dynamically: every time it receives a packet with local
addresses (IP within accepted bands for private networks, Table 14) and with global destinations (valid or
global IP, Table 15), address translation will occur.
Type of address
Beginning of band
End of band
A Class
10.0.0.0
10.255.255.255
B Class
172.16.0.0
172.31.255.255
C Class
192.168.0.0
192.168.255.255
Table 14. IP addresses for private networks
Type of address
Beginning of band
End of band
A Class
1.0.0.0
126.255.255.255
B Class
128.0.0.0
191.255.255.255
C Class
192.0.0.0
223.255.255.255
C Class (Multicast)
224.0.0.0
239.255.255.255
E Class
240.0.0.0
255.255.255.255
Table 15. Valid or global IP addresses
NAT converts local addresses into an interface address through which data reach the fixed IP destination
(usually, this path is indicated in the configuration of gateway default). In the return path, the equipment
replaces address/port data according to the multiplexer that sent the waiting packet.