pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/29751 )
Change subject: RFC: Introduce support for MGW-pinning per BTS ......................................................................
RFC: Introduce support for MGW-pinning per BTS
This feature allows pinning each BTS to a specific MGW from the configured pool. The pinning can be soft or hard (strict). If strict pinning is not set, the configured MGW is selected with priority, but other MGWs can still be selected during each call setup if the preferred MGW is found not available at that time, hence avoiding denial of service for the entire BTS if that MGW goes down. If strict mode is selected, the call will be refused if the configured preferred MGW is not available at the time the call is set up.
It is useful to use this feature when Osmux is configured between the BTS and the BSC and an MGW pool is in use. This way the BSC is capable of grouping all the calls of a BTS towards one MGW, hence taking advantage of the Osmux trunking optimizations to reduce link data usage (AMR payload of several concurrent calls ending up sharing the same underlaying UPD packet). Furthermore, this allows the operator to intelligently spread load over the MGW pool in order to avoid ending up with more than 256 concurrent Osmux circuits on any of the co-located MGWs in the pool (maximum supported at the moment).
Related: SYS#5987 Change-Id: I9a7a5af72795faed0d12d9d73b59951b6a0e9c7d --- M include/osmocom/bsc/bts.h M src/osmo-bsc/bsc_subscr_conn_fsm.c M src/osmo-bsc/bts.c M src/osmo-bsc/bts_vty.c 4 files changed, 91 insertions(+), 1 deletion(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/51/29751/1
diff --git a/include/osmocom/bsc/bts.h b/include/osmocom/bsc/bts.h index b690652..d71d18f 100644 --- a/include/osmocom/bsc/bts.h +++ b/include/osmocom/bsc/bts.h @@ -580,6 +580,10 @@ /* exclude the BTS from the global RF Lock handling */ int excl_from_rf_lock;
+ /* MGW specificities for this BTS: */ + int mgw_pool_target; /* Pin to specific MGW. -1 = wildcard */ + bool mgw_pool_target_strict; /* Only allow pinned MGW */ + /* supported codecs beside FR */ struct bts_codec_conf codec;
diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c b/src/osmo-bsc/bsc_subscr_conn_fsm.c index 21988ce..2a4e387 100644 --- a/src/osmo-bsc/bsc_subscr_conn_fsm.c +++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c @@ -621,6 +621,62 @@ return true; }
+static struct mgcp_client *select_mgw(struct gsm_subscriber_connection *conn, struct gsm_lchan *for_lchan) +{ + struct mgcp_client_pool_member *mgcp_pmemb; + struct mgcp_client *mgcp_client; + struct gsm_bts *bts = for_lchan->ts->trx->bts; + + /* If BTS is not pinned to a given MGW, let regular allocation which + * spreads load over available MGWs: */ + if (bts->mgw_pool_target == -1) + goto pick_any; + + /* BTS is pinned to an MGW, retrieve pointer to it: */ + mgcp_pmemb = mgcp_client_pool_find_member_by_nr(conn->network->mgw.mgw_pool, bts->mgw_pool_target); + if (!mgcp_pmemb) { + if (!bts->mgw_pool_target_strict) { + LOGPFSML(conn->fi, LOGL_NOTICE, + "mgw pool-target %u not found! selecting another one.\n", bts->mgw_pool_target); + goto pick_any; + } else { + LOGPFSML(conn->fi, LOGL_ERROR, "mgw pool-target %u not found!\n", bts->mgw_pool_target); + return NULL; + } + } + if (mgcp_client_pool_member_is_blocked(mgcp_pmemb)) { + if (!bts->mgw_pool_target_strict) { + LOGPFSML(conn->fi, LOGL_NOTICE, + "mgw pool-target %u is administratively blocked! selecting another one.\n", + bts->mgw_pool_target); + goto pick_any; + } else { + LOGPFSML(conn->fi, LOGL_ERROR, "mgw pool-target %u is administratively blocked!\n", + bts->mgw_pool_target); + return NULL; + } + } + + mgcp_client = mgcp_client_pool_member_get(mgcp_pmemb); + if (!mgcp_client) { + if (!bts->mgw_pool_target_strict) { + LOGPFSML(conn->fi, LOGL_NOTICE, + "mgw pool-target %u is not connected! selecting another one.\n", + bts->mgw_pool_target); + goto pick_any; + } else { + LOGPFSML(conn->fi, LOGL_ERROR, "mgw pool-target %u is not connected!\n", + bts->mgw_pool_target); + return NULL; + } + } + return mgcp_client; + +pick_any: + mgcp_client = mgcp_client_pool_get(conn->network->mgw.mgw_pool); + return mgcp_client; +} + /* Make sure a conn->user_plane.mgw_endpoint is allocated with the proper mgw endpoint name. For * SCCPlite, pass in msc_assigned_cic the CIC received upon BSSMAP Assignment Command or BSSMAP Handover * Request form the MSC (which is only stored in conn->user_plane after success). Ignored for AoIP. */ @@ -640,7 +696,7 @@
if (gscon_is_sccplite(conn) || gscon_is_aoip(conn)) { /* Get MGCP client from pool */ - mgcp_client = mgcp_client_pool_get(conn->network->mgw.mgw_pool); + mgcp_client = select_mgw(conn, for_lchan); if (!mgcp_client) { LOGPFSML(conn->fi, LOGL_ERROR, "cannot ensure MGW endpoint -- no MGW configured, check configuration!\n"); diff --git a/src/osmo-bsc/bts.c b/src/osmo-bsc/bts.c index b7d3c3c..8d4b8c8 100644 --- a/src/osmo-bsc/bts.c +++ b/src/osmo-bsc/bts.c @@ -331,6 +331,9 @@ INIT_LLIST_HEAD(&bts->oml_fail_rep); INIT_LLIST_HEAD(&bts->chan_rqd_queue);
+ /* Don't pin the BTS to any MGW by default: */ + bts->mgw_pool_target = -1; + /* Enable all codecs by default. These get reset to a more fine grained selection IF a * 'codec-support' config appears in the config file (see bsc_vty.c). */ bts->codec = (struct bts_codec_conf){ diff --git a/src/osmo-bsc/bts_vty.c b/src/osmo-bsc/bts_vty.c index 0e14284..3bb0375 100644 --- a/src/osmo-bsc/bts_vty.c +++ b/src/osmo-bsc/bts_vty.c @@ -3000,6 +3000,25 @@ return CMD_WARNING; }
+DEFUN_USRATTR(cfg_bts_mgw_pool_target, + cfg_bts_mgw_pool_target_cmd, + X(BSC_VTY_ATTR_NEW_LCHAN), + "mgw pool-target <0-255> [strict]", + "MGW configuration for this specific BTS\n" + "Pin BTS to use a single MGW in the pool\n" + "Reference Number of the MGW (in the config) to pin to\n" + "Strictly prohibit use of other MGWs if the pinned one is not available") +{ + struct gsm_bts *bts = vty->index; + int mgw_nr = atoi(argv[0]); + bool strict = argc > 1; + + bts->mgw_pool_target = mgw_nr; + bts->mgw_pool_target_strict = strict; + + return CMD_SUCCESS; +} + #define TNUM_STR "T-number, optionally preceded by 't' or 'T'\n" DEFUN_ATTR(cfg_bts_t3113_dynamic, cfg_bts_t3113_dynamic_cmd, "timer-dynamic TNNNN", @@ -4552,6 +4571,13 @@ VTY_NEWLINE); }
+ if (bts->mgw_pool_target > -1) { + vty_out(vty, " mgw pool-target %u%s%s", + bts->mgw_pool_target, + bts->mgw_pool_target_strict ? " strict" : "", + VTY_NEWLINE); + } + config_write_bts_gprs(vty, bts);
if (bts->excl_from_rf_lock) @@ -4814,6 +4840,7 @@ install_element(BTS_NODE, &cfg_bts_amr_hr_hyst3_cmd); install_element(BTS_NODE, &cfg_bts_amr_hr_start_mode_cmd); install_element(BTS_NODE, &cfg_bts_osmux_cmd); + install_element(BTS_NODE, &cfg_bts_mgw_pool_target_cmd); install_element(BTS_NODE, &cfg_bts_pcu_sock_cmd); install_element(BTS_NODE, &cfg_bts_acc_rotate_cmd); install_element(BTS_NODE, &cfg_bts_acc_rotate_quantum_cmd);
-
pespin