PairGain CRA-C, User Manual

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Network and Management Overview
Megabit Modem CRA-C User Manual 53
You can enable or disable Spanning Tree on the Bridge/Router Configuration
Menu. The Megabit Modem CRA-C uses the Spanning Tree defaults shown in
Table 16. These values are user-configurable through SNMP as part of the
Spanning Tree group in RFC 1493.
Table 16. Spanning Tree Defaults
Spanning Tree Attribute Default Value
ST Bridge Priority Hx0000
ST Max Age 30 seconds
ST Hello Time 10 seconds
ST Hold Time 10 second
ST Forward Delay 10 second
ST Port 1 Priority (LAN) 0
ST Port 2 Priority (ADSL) 0
ST Port Path Cost 1
Static IP Routing
Through the static IP routing feature, you can configure the Megabit Modem
CRA-C as an IP router with statically programmed route entries. You can
enable this function as a security feature to prevent eavesdropping and to
provide broadcast filtering, as well as to specify multiple destination gateways.
When static IP routing is enabled, you can access only specific remote IP
subnets or hosts.
Since IP routers make forward or filter decisions based on the network-layer
IP address instead of the MAC hardware address, MAC-level broadcast frames
are prevented from reaching unwanted destinations in the network. The
example in Figure 10 shows a simple Internet Service Provider (ISP) site that
uses the static IP routing feature to filter MAC-level broadcast frames sourced
by ISP Subscriber A from reaching ISP Subscriber B.