Change in osmo-gsm-manuals[master]: Copy mgwpool.adoc from osmo-bsc.git

pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-gsm-manuals/+/29819 ) Change subject: Copy mgwpool.adoc from osmo-bsc.git ...................................................................... Copy mgwpool.adoc from osmo-bsc.git Copied from osmo-bsc.git/doc/manuals/chapters/mgwpool.adoc, version from Change-Id Id0d292506e8b2a888c8d7a682a38db80e9d0933a Related: SYS#5987 Change-Id: Ieda0d4bfe6fc90da6e19c791d8ec2da89427ba3b --- A common/chapters/mgwpool.adoc 1 file changed, 239 insertions(+), 0 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-gsm-manuals refs/changes/19/29819/1 diff --git a/common/chapters/mgwpool.adoc b/common/chapters/mgwpool.adoc new file mode 100644 index 0000000..c429159 --- /dev/null +++ b/common/chapters/mgwpool.adoc @@ -0,0 +1,239 @@ +[[mgw_pooling]] +== MGW Pooling + +{program-name} is able to use a pool of media gateway (MGW) instances. +The aim of MGW pooling is to evenly distribute the RTP voice stream load across +multiple MGW instances. This can help to scale out over multiple VMs or physical +machines. Until osmo-mgw includes multithreading support, it may also be used to +scale-out to multiple cores on a single host. + +The load distribution is managed in such a way that when a new call is placed, +the pool will automatically assign the call to the MGW with the lowest load. + +MGW pooling is recommended for larger RAN or CN installations. For small networks +and lab installations the classic method with one MGW per BSC offers sufficient +performance. + +=== MGW pool VTY configuration + +In {program-name} the MGW is controlled via an MGCP-Client. The VTY commands to +configure the MGCP-Client are part of the several 'mgw' nodes, one per +MGCP-Client to set up. + +To setup an MGW pool, the user must first install multiple OsmoMGW instances, so +that they won’t interfere with each other. This can be done using different +local host IP addresses or different ports. When OsmoMGW is installed from +packages, the systemd configuration may also require adjustment. + +By default, MGCP-Client will use whatever source IP address is resolved by the +kernel routing subsystem, and will also ask the kernel to pick a free UDP port. + +Example configuration with two MGCP-Client instances in a pool: +---- + mgw 0 + description media-gw-0 <2> + remote-ip 127.0.0.1 + remote-port 2432 + local-ip 127.0.0.1 + local-port 2431 + endpoint-domain mgw0 <1> + mgw 1 + description media-gw-1 <2> + remote-ip 127.0.0.1 + remote-port 2430 + local-ip 127.0.0.1 + local-port 2429 + endpoint-domain mgw1 <1> +---- + +<1> When working with multiple MGW / MGCP-Client instances, the domain name for +each MGW should be different. Otherwise it won't be possible to distinguish the +endpoint names in the log. It should also be noted that the domain name must +match the configuration of the related OsmoMGW instance. + +<2> It is also possible to assign a descriptive name to each MGW instance. The +MGCP client specific log lines will then use this name as logging context. If +no description is set, the domain name will be used. + +=== MGW pool management + +The MNGW pool is fully runtime-manageable. The only limitation +is that an MGCP-Client can not be restarted or removed as long as it is serving +calls (see also: <<mgw_pooling_blocking>>). + +==== MGW pool status + +The VTY implements a 'show mgw-pool' command that lists the currently configured +MGW pool members, their status and call utilization. The following snippet shows +an output example run on OsmoBSC, but it should be also available on other +applications supporting the MGW pooling VTY featues: + +---- +OsmoBSC> show mgw-pool +% MGW-Pool: +% MGW 0:media-gw-0 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 1 +% MGW 1:media-gw-1 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 0 +---- + +==== Adding an MGW / MGCP-Client to the MGW pool + +To add a new MGCP-Client to the pool, the 'mgw' node is used. Like with the +'bts' or the 'msc' node a reference number is used that usually starts at 0. +However it is still possible to assign any number from 0-255. The enumeration +also may contain gaps. The following snippet shows an output example run on +OsmoBSC, but it should be also available on other applications supporting the +MGW pooling VTY featues: + +---- +OsmoBSC> enable +OsmoBSC# configure terminal +OsmoBSC(config)# network +OsmoBSC(config-net)# mgw 2 +OsmoBSC(config-mgw)# ? + local-ip local bind to connect to MGW from + local-port local port to connect to MGW from + remote-ip remote IP address to reach the MGW at + remote-port remote port to reach the MGW at + endpoint-domain Set the domain name to send in MGCP messages, e.g. the part 'foo' in 'rtpbridge/*@foo'. + reset-endpoint Add an endpoint name that should be reset (DLCX) on connect to the reset-endpoint list,e.g. 'rtpbridge/*' +---- + +The newly added MGW will immediately appear in the mgw-pool list but it won't +be used until its configuration finished by reconnecting it. + +---- +% MGW-Pool: +% MGW 0:media-gw-0 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 2 +% MGW 1:media-gw-1 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 3 +% MGW 2:mgw <1> +% mgcp-client: disconnected +% service: unblocked +% ongoing calls: 0 +---- + +<1> In this example a description is not set yet, so the domain name ("mgw") +is displayed. + +==== Reconnecting an MGW / MGCP-Client + +It may become necessary to reconnect an MGCP-Client. This is the case when the +VTY configuration was changed at runtime. In order to make the changes effective +the MGW configuration must be reloaded by reconnecting the MGW connection. Also +newly created MGW instances require a reconnect once their configuration is +done. + +To reconnect an MGCP-Client use the 'reconnect' VTY command: +---- +OsmoBSC# mgw 2 reconnect +---- + +The mgcp-client status should immediately change to 'connected'. The MGW is now +ready to be used for new calls. + +---- +OsmoBSC# show mgw-pool +% MGW-Pool: +% MGW 0:media-gw-0 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 2 +% MGW 1:media-gw-1 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 3 +% MGW 2:mgw +% mgcp-client: connected +% service: unblocked +% ongoing calls: 0 +---- + +It should be noted that MGCP a protocol is used via UDP, the connect only +happens locally to forward the UDP datagrams properly. Also (unless a reset +endpoint is configured like in the example config above) there will be no +immediate interaction with the MGW. However, the log should at least confirm +the the connect worked and the MGCP client has been created successfully. + +---- +Mon Aug 2 17:15:00 2021 DLMGCP mgcp_client.c:788 MGCP client: using endpoint domain '@mgw' +Mon Aug 2 17:15:00 2021 DLMGCP mgcp_client.c:908 MGCP GW connection: r=127.0.0.1:2427<->l=127.0.0.1:2727 +---- + +It is strongly advised to check the activity on the related MGW and to follow +the log in order to see that the communication between {program-name} and the MGW is +working correctly. + +[[mgw_pooling_blocking]] +==== Blocking an MGW / MGCP-Client + +If it becomes apparent that an MGCP-Client must be restarted or removed from +the config (maintenance) the operator can put that MGCP-Client into a blocked +mode. A blocked MGCP-Client will still serve the ongoing calls but it will not +be picked for the assignment of new calls. + +To block an MGCP-Client use the 'block' VTY command: +---- +OsmoBSC# mgw 2 block +OsmoBSC# show mgw-pool +% MGW-Pool: +% MGW 0:media-gw-0 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 11 +% MGW 1:media-gw-1 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 12 +% MGW 2:mgw +% mgcp-client: connected +% service: blocked +% ongoing calls: 10 +---- + +When the number of ongoing calls has tapered off, the MGW / MGCP-Client can be +restarted or removed if necessary. + +---- +OsmoBSC# show mgw-pool +% MGW-Pool: +% MGW 0:media-gw-0 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 15 +% MGW 1:media-gw-1 +% mgcp-client: connected +% service: unblocked +% ongoing calls: 14 +% MGW 2:mgw +% mgcp-client: connected +% service: blocked +% ongoing calls: 0 +---- + +If the blockade should be reverted, the 'unblock' VTY command can be used in +the same way to remove the blockade. (Reconnecting will not remove the +blockade.) + +==== Removing an MGW / MGCP-Client + +An MGCP-Client is removed from the pool using the 'no mgw' command from the +configure terminal. The MGCP-Client instance will automatically be terminated +and the related resources are freed. The only requirement is that there are no +ongoing calls on the selected instance. + +---- +OsmoBSC# configure terminal +OsmoBSC(config)# network +OsmoBSC(config-net)# no mgw 2 +---- -- To view, visit https://gerrit.osmocom.org/c/osmo-gsm-manuals/+/29819 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-gsm-manuals Gerrit-Branch: master Gerrit-Change-Id: Ieda0d4bfe6fc90da6e19c791d8ec2da89427ba3b Gerrit-Change-Number: 29819 Gerrit-PatchSet: 1 Gerrit-Owner: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-MessageType: newchange