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Table Of Contents
Main DECnet Routing Configuration Dialog Box
DECnet: Ethernet Configuration Dialog Box
DECnet: WAN Configuration Dialog Box
DECnet Routing & Bridging
Main DECnet Routing Configuration Dialog Box
To access this dialog box (Figure 5-1), select Global/DECnet Routing in the Device View.
Figure 5-1 Main DECnet Routing Configuration Dialog Box
DECnet On
This checkbox controls how DECnet packets are handled for this router.
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If checked, then DECnet packets received on any interface in the router which has DECnet turned on will be routed to the correct interface.
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Area
DECnet areas create a logical group of DECnet nodes. A DECnet area may include one or more physical network segments. The Area value must be within the range of 1 to 63.
The area information is specific to this individual router and, along with the Node number, uniquely identifies it on the network. If you are unsure what value to use here, check with your network administrator.
Node
Each device in an area must have a unique node number. The Node value must be within the range of 1 to 1023.
The node number is specific to this individual router and, along with the Area number, uniquely identifies it on the network. If you are unsure what value to use here, check with your administrator.
Using the same Area:Node combination as an address for two different devices can cause difficult-to-diagnose problems on your network. You should carefully track the assignment of this information for devices on your DECnet network.
Hello Timer
DECnet hello messages tell end nodes which routers are available to route packets. This parameter tells the router how frequently it should send hello messages on its LAN interfaces.
The Hello Timer value is also inserted into the hello messages themselves. Once an end node has received a hello message from a router, it begins to track the availability of that router. If an end node does not hear an additional hello message within 3 timer periods, it assumes that this router is no longer available.
The default value for this parameter is 30 seconds.
The Hello Timer values for individual WAN interfaces are set in separate windows. For more information, see the "DECnet: WAN Configuration Dialog Box" section.
Routing Timer
DECnet routing messages are exchanged between routers and contain routing table information including node numbers, hello timer values, hop counts and costs. This parameter tells the router how frequently it should send routing messages on its LAN interfaces.
The default value for this parameter is 120 seconds.
The Routing Timer values for individual WAN interfaces are set in separate windows. For more information, see the "DECnet: WAN Configuration Dialog Box" section.
Max Addresses
This is the maximum number of node addresses allowed for this particular area. The default value for this parameter is 1023.
By limiting the number of addresses, a network administrator can limit the size of the internal routing table and the size of the routing messages sent to other routers.
Generally, all routers on the network should be consistent and use the same value for this parameter. This number should be at least as large as the number entered for this router's node number.
DECnet: Ethernet Configuration Dialog Box
Bridging operates on physical network addresses (such as Ethernet addresses), rather than logical addresses (such as DECnet addresses). From the standpoint of DECnet networking, router interfaces which are set to bridge DECnet between themselves appear as a single logical entity.
Thus, a router's "DECnet Bridge Group" is made up of all of the physical network interfaces in a router which have been set to bridge DECnet.
Logically, the DECnet Bridge Group is treated by the router as an interface (Bridge 0). The settings in the Main DECnet Routing Configuration dialog box (Figure 5-1) determine the DECnet parameters for all of the physical network interfaces which make up the DECnet Bridge Group. This is shown schematically in Figure 5-2.
Figure 5-2 Bridge Logical Diagram
To access the DECnet: Ethernet Configuration dialog box (Figure 5-3), select Ethernet/DECnet Routing in the Device View.
The Cisco VPN 5000 Manager only provides this configuration dialog box for routers which support bridging. Ethernet parameters for other routers are set globally in the Main DECnet Routing Configuration dialog box.
Figure 5-3 DECnet: Ethernet Configuration Dialog Box
DECnet Routing/Bridging/Off
This set of radio buttons controls how DECnet packets are handled for this interface.
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The DECnet Bridging radio button will be grayed out unless bridging has been turned on globally for the device using the Main Bridging Configuration dialog box (under Global/Bridging) and locally on this interface using the Bridging: Ethernet dialog box (under Ethernet/Bridging).
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DECnet: WAN Configuration Dialog Box
To access this dialog box (Figure 5-4), select WAN/DECnet Routing in the Device View.
Figure 5-4 DECnet: WAN Configuration Dialog Box
DECnet On/Bridging/Off
This set of radio buttons controls how DECnet packets are handled for this interface.
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The DECnet Bridging radio button will be grayed out unless bridging has been turned on globally for the device using the Main Bridging Configuration dialog box (under Global/Bridging) and locally on this interface using the Bridging: WAN dialog box (under WAN/Bridging).
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Hello Timer
DECnet hello messages tell end nodes which routers are available to route packets. This parameter tells the router how frequently it should send hello messages on this interface.
The Hello Timer value is also inserted into the hello messages themselves. Once an end node has received a hello message from a router, it begins to track the availability of that router. If an end node does not hear an additional hello message within 3 timer periods, it assumes that this router is no longer available.
The default value for this parameter is 30 seconds. The maximum value is 8191 seconds (approximately 2 hours and 15 minutes).
For dial-on-demand links, this parameter should be set to the longest period practical, since the router will dial the remote end each time one of these packets is sent.
Routing Timer
DECnet routing messages are exchanged between routers and contain routing table information including node numbers, hello timer values, hop counts and costs. This parameter tells the router how frequently it should send routing messages on this interface.
The default value for this parameter is 120 seconds. The maximum value is 8191 seconds (approximately 2 hours and 15 minutes).
For dial-on-demand links, this parameter should be set to the longest period practical, since the router will dial the remote end each time one of these packets is sent.
