UDLDを究める:(17) UDLD のデバッグ (3) Unidirectional(片方向)を検知する(アグレッシブ・モード)

debug コマンドを使って、Unidirectional を検知してから、ErrDisable されるまでの流れを見ていきます。

a
Catalyst のコンソールで、debug udld events とdebug udld packets コマンドを実行します。

Catalyst#debug udld events
UDLD events debugging is on
Catalyst#debug udld packets
UDLD packets debugging is on
Catalyst#








Catalyst-A

Bi-directional になっています。

*Mar 19 19:16:12: allNeighborsAgedOutEvent during link up. (Gi0/11) 
*Mar 19 19:16:12: Phase set from ADV to LUP because all neighbors aged out (Gi0/11)
*Mar 19 19:16:12: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:12: Pr (Gi0/11)
*Mar 19 19:16:12: prev = 0 entry = 11E588C next = 0 exp_time = 0 (Gi0/11)
*Mar 19 19:16:12: udsb->cache = 0xDCA128 (Gi0/11)
*Mar 19 19:16:12: timeout timer = 7 (Gi0/11)
*Mar 19 19:16:12: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:12: Pr (Gi0/11)
*Mar 19 19:16:13: timeout timer = 6 (Gi0/11)
*Mar 19 19:16:13: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:13: Pr (Gi0/11)
*Mar 19 19:16:14: timeout timer = 5 (Gi0/11)
*Mar 19 19:16:14: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:14: Pr (Gi0/11)
*Mar 19 19:16:15: timeout timer = 4 (Gi0/11)
*Mar 19 19:16:15: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:15: Pr (Gi0/11)
*Mar 19 19:16:16: timeout timer = 3 (Gi0/11)
*Mar 19 19:16:16: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:16: Pr (Gi0/11)
*Mar 19 19:16:17: timeout timer = 2 (Gi0/11)
*Mar 19 19:16:17: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:17: Pr (Gi0/11)
*Mar 19 19:16:18: timeout timer = 1 (Gi0/11)
*Mar 19 19:16:18: UDLD send probe message, flags = rec_timeout | resynch (Gi0/11)
*Mar 19 19:16:18: Pr (Gi0/11)
*Mar 19 19:16:19: timeout timer = 0 (Gi0/11)
*Mar 19 19:16:19: Phase set to udld_advertisement from phase udld_link_up in aggresive mode after all neighbors aged out. (Gi0/11)
*Mar 19 19:16:19: UDLD send flush message, flags = 0 (Gi0/11)
*Mar 19 19:16:19: F (Gi0/11)
*Mar 19 19:16:19: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi0/11, aggressive mode failure detected
*Mar 19 19:16:19: %PM-4-ERR_DISABLE: udld error detected on Gi0/11, putting Gi0/11 in err-disable state
*Mar 19 19:16:19: Port UDLD set error disabled (Gi0/11)
*Mar 19 19:16:19: Phase set to udld_advertisement after timer_expired. (Gi0/11)
*Mar 19 19:16:20: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/11, changed state to down
*Mar 19 19:16:20: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Mar 19 19:16:21: %LINK-3-UPDOWN: Interface GigabitEthernet0/11, changed state to down

① 対向機器からUDLD PDU を受信しなくなり、エントリーをテーブルから消去しました。

② Link Up フェイズへ移行しました。

③ 空のEcho TLV を持ったProbe を送信し始めます。 Recommended Timeout フラグとReSynch フラグが立っています。

④ 空のEcho TLV を持ったProbe を8 回送信し終わりました。

⑤ Flush を送信しました。

⑥ GigabitEthernet0/11 をErrDisable にしました。