sigtran-osmocom.adoc: Improve route section

Change-Id: Ice7c6f09bbf37c032af9a7f6f21d7994ce53ea82
---
M common/chapters/sigtran-osmocom.adoc
1 file changed, 16 insertions(+), 3 deletions(-)


git pull ssh://gerrit.osmocom.org:29418/osmo-gsm-manuals refs/changes/88/41088/1

diff --git a/common/chapters/sigtran-osmocom.adoc b/common/chapters/sigtran-osmocom.adoc
index ddba669..32d03cf 100644
--- a/common/chapters/sigtran-osmocom.adoc
+++ b/common/chapters/sigtran-osmocom.adoc
@@ -381,11 +381,16 @@
 
 === Osmocom SS7 Routes
 
-An Osmocom SS7 Route routes traffic with a matching destination point
-code and point code mask (similar to IP Address + Netmask) towards a
-specified SS7 Linkset or Application Server.  The Linkset or
+An Osmocom SS7 Route holds information to route traffic with a matching
+destination point code and point code mask (similar to IP Address + Netmask)
+towards a specified SS7 Linkset or Application Server.  The Linkset or
 Application Servers are identified by their name.
 
+Routes are inserted in a routing table, where they are ordered first based
+on prefix mask length (longest prefix first) and then on priority (lowest value first).
+As a result, more specific routes (eg. a single Point Code) will match and
+be used before more generic ones (eg. a subnet).
+
 .Major Attributes of an Osmocom SS7 Application Server Process
 [options="header",cols="25%,75%"]
 |====
@@ -393,8 +398,16 @@
 |Point Code|Destination Point Code for this route
 |Mask|Destination Mask for this route (like an IP netmask)
 |Linkset/AS Name|Destination Linkset or AS, identified by name
+|Priority|Priority of the route in the routing table; lower value means higher priority
 |====
 
+The `show cs7 instance <0-15> route` command can be used on the
+VTY to obtain the list of routes inserted in the system routing table.
+
+The `show cs7 instance <0-15> route-lookup <DPC> from <OPC> sls <SLS>` command
+can be used on the VTY to test and debug routing of specific traffic on the
+currently running routing table, similar to what `ip route get` linux command
+does in the IP world.
 
 === Osmocom SCCP Instances
 

