| Oracle® Communications EAGLE Database Administration - SS7 User's Guide Release 46.7 E97335 Revision 1 |
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| Oracle® Communications EAGLE Database Administration - SS7 User's Guide Release 46.7 E97335 Revision 1 |
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Network routing allows the user to provision a single routeset that can used for all MSUs destined to members of that network. The advantages of network routing are:
A EAGLE user can connect to a remote network by provisioning a single route table element. As the remote network grows, the EAGLE user does not have to add new route table entries for each new point code in the remote network.
Note:
Network routing can be used only with ANSI point codes. A network routing point code cannot be provisioned as a proxy point code.Types of Routing Strategies Available
The EAGLE currently allows a user to provision two types of routing strategies:
This feature allows the user to provision a third type of routing strategy, network routing.
It is possible to provision full point code entries, cluster entries, and network entries for members of the same network. Any overlaps in the routing strategies are handled by a specific searching hierarchy.
All of these route table entries can coexist:
The searching hierarchy tries to match against a full point code entry first, followed by a cluster entry, and finally a network entry. In the preceding example, when the EAGLE routes an MSU destined for 8-1-1, it uses the full point code entry; when the EAGLE routes an MSU destined for 8-1-2 it uses the cluster entry; and when the EAGLE routes an MSU destined for 8-2-2, it uses the network entry.
Applications
Network routing is very useful when the destination node is very far away from the source node. The reliability of network routing increases when the destination is further away. Notice that in Figure 2-27, routing from network A is more reliable to nodes in network C than to nodes in network B.
Figure 2-27 Example of Network Routing Reliability
If the nodes in network A use network routing for network C, network A can still route traffic to SSP C, even if two linksets fail. In this example, one of the A-linksets to SSP C and the C-linkset between node C1 and node C2 fail. In this case, the EAGLE in network A continues to route half its traffic to node B1, and half to node B2. Node B1 and node B2 (which do not use network routing) route all traffic for SSP C through node C2.
If the nodes in network A use network routing for network B, traffic going to SSP B may be lost if two linksets fail. In this example, one of the A-linksets to SSP B and the C-linkset between node B1 and node B2 fail. In this case, the EAGLE in network A continues to route half its traffic to node B1, and half to node B2. Traffic for SSP B routed through node B1 is discarded, resulting in message loss.
Route Availability
A route is one path to a destination. A routeset is a list of paths to a destination. Route availability consists of two parts:
Remote availability is affected by TFx network management messages. Local availability is affected by linkset failures and recoveries. TFx messages do not affect point codes accessed by network route entries. Therefore, for network route entries, route availability consists of only local availability. The highest priority linkset available for traffic is used for routing MSUs, regardless of the remote availability of that route.
Figure 2-28 Potential Routing Network Failure
In the example in Figure 2-28, linksets LS-C and LS-D form a combined route to network route 7-*-*. Because 7-*-* is a network route, the EAGLE always considers the non-adjacent status of the routes to be allowed. In the example shown, the EAGLE routes traffic destined to 7-7-1 over LS-C and LS-D. The EAGLE ignores TFPs concerning 7-7-1 or TCPs concerning 7-7-*.
Point Code Availability
A point code that is accessed by a network route entry is considered available if there is any linkset in the routeset that is available for traffic.
Local Link Congestion
This feature has no impact on the generation of TFC messages. A TFC is generated concerning point code X-Y-Z, even if X-Y-Z is routed using a network route entry.
Remote Congestion
Because the EAGLE has global title capabilities, it is possible for the EAGLE to receive a TFC concerning a point code that is accessed by a network route entry. Network route entries are not affected by TFC messages.
Broadcast Transfer Messages
The EAGLE does not broadcast TFx messages for network route entries.
Response Method Transfer Messages
The EAGLE sends response method TFx messages for network routes as follows:
If the EAGLE receives an MSU that is accessed by a network route entry, and that network route is Prohibited, the EAGLE sends a response method TFP or TCP message, as follows:
The EAGLE sends response method TCPs or TFPs at a rate of one TCP or TFP per signaling link during the level 3 T8 timer period for each network route.
For example, in Figure 2-28, the network route for 7-*-* becomes Prohibited due to the failure of LS-B, LS-C, and LS-D. When the EAGLE receives an MSU from X destined for 7-7-1, the EAGLE sends a response method TCP concerning 7-7-*. When the EAGLE receives an MSU from X destined for 7-8-2, the EAGLE sends a response method TCP concerning 7-8-*.
If the EAGLE receives an MSU that is accessed by a network route entry, and the EAGLE detects danger of circular routing, the EAGLE sends a response method TFP or TCP message, as follows:
The EAGLE sends response method TCPs at a rate of one TCP per signaling link during the level 3 T8 timer period for each network route.
For example, in Figure 2-28, all linksets are available. If the EAGLE receives an MSU from node C destined for 7-7-1, the EAGLE detects danger of circular routing, and sends a response method TCP concerning 7-7-*. The EAGLE also discards the MSU.
If the EAGLE receives an MSU that is accessed by a network route entry, and that network route is Restricted, the EAGLE sends a one-time response method TFR or TCR message, as follows:
For example, in Figure 2-28, the network route for 7-*-* becomes Restricted due to the failure of LS-C and LS-D. When the EAGLE receives an MSU from X destined for 7-7-1, the EAGLE sends a response method TCR concerning 7-7-*, then routes the MSU over LS-B. When the EAGLE next receives an MSU from X destined for 7-8-2, the EAGLE does not send a response, and routes the MSU over LS-B.
Reception of Transfer Messages
The EAGLE does not apply received transfer messages to a network route.
For example, in Figure 2-28, if the EAGLE receives a TFP concerning 7-7-1, it has no effect on the routing status of 7-*-*. The EAGLE continues to send MSUs destined to 7-*-*, including MSUs destined to 7-7-1, on LS-C.
As another example, if the EAGLE receives a TCP concerning 7-8-*, it has no effect on the routing status of 7-*-*. The EAGLE continues to send MSUs destined to 7-*-*, including MSUs destined to 7-8-2, on LS-C.
Reception of an RSx Message
If a routeset test (RSP or RSR) is received, a full point code reply (TFx) is generated. The responses to RSP/RSR have been changed according to Table 2-13. Note that the searching hierarchy applies.
Table 2-13 Reception of an RSx Message
| Concerned Point Code is: | Result |
|---|---|
| Found by a full point code match |
No change to existing rules. |
| Found by a cluster match |
No change to existing rules. |
| Found by a network match |
Send a TFx message based on the current routeset status.
Otherwise:
|
| Not found |
No change to existing rules. Send a TFP. |
Reception of an RCx Message
If a routeset cluster test (RCP or RCR) is received, a cluster reply (TCx) is generated. The responses to RCP/RCR have been changed according to Table 2-14. Note that the searching hierarchy applies.
Table 2-14 Reception of an RCx Message
| Concerned Point Code is: | Result |
|---|---|
| Found by a cluster match |
No change to existing rules. |
| Found by a network match |
Send a TCx message based on the current routeset status.
Otherwise:
|
| Not found |
No change to existing rules. Send a TCP. |
Administration
The network routing feature must be on, before a network routing point code can be provisioned in the database. This can be verified with the entry NRT = on in the output of the rtrv-feat command. If the network routing feature is not on, NRT = off, it must be turned on with the chg-feat command using the nrt=on parameter. Once the network routing feature is on, the network routing point code can be provisioned in the database like any other destination point code. Routes can then be assigned to the network routing point code like any other destination point code. For more information on provisioning network routing point codes, see the Adding a Network Routing Point Code procedure.
Note:
Once the network routing feature is turned on using thechg-feat command, it cannot be turned off. When using the network routing feature, limited network management is provided for point codes not covered by full point code routing, cluster routing, or nested cluster routing.The network routing feature must be purchased before you turn this feature on with the chg-feat command. If you are not sure if you have purchased the network routing feature, contact your Oracle Sales Representative or Account Representative.
