In questo documento viene descritto come configurare lo switch peer sugli switch Cisco Nexus serie 7000 in modo da consentire le connessioni non virtuali tramite canale (non vPC) al bilanciamento del carico tra le VLAN.
Quando lo switch peer è abilitato, ciascuno switch Nexus 7000 condivide un ID bridge virtuale, che consente a entrambi gli switch di fungere da radice per la VLAN. Per i dispositivi con una connessione a ciascuno switch Nexus 7000 nel dominio vPC che non sono in grado di effettuare il channeling della porta, la topologia di layer 2 (L2) si basa sul protocollo Spanning Tree Protocol (STP) per bloccare i collegamenti ridondanti. La funzionalità dello switch peer consente configurazioni pseudo-STP per consentire connessioni non vPC per il bilanciamento del carico degli stati STP tra i due switch Nexus 7000. In questo documento viene descritto in dettaglio il motivo delle configurazioni pseudo-STP e il loro effetto sui collegamenti non vPC e vPC.
Una combinazione di collegamenti vPC e non vPC viene definita configurazione ibrida.
Gli indirizzi MAC di ciascuno switch utilizzati nell'esempio di configurazione riportato in questo documento sono:
Cisco raccomanda la conoscenza dei seguenti argomenti:
Per la stesura del documento, sono stati usati switch Cisco Nexus serie 7000 con Supervisor 1 Module.
Le informazioni discusse in questo documento fanno riferimento a dispositivi usati in uno specifico ambiente di emulazione. Su tutti i dispositivi menzionati nel documento la configurazione è stata ripristinata ai valori predefiniti. Se la rete è operativa, valutare attentamente eventuali conseguenze derivanti dall'uso dei comandi.
Questo è un diagramma di rete di una configurazione ibrida senza peer switch abilitato. Entrambi gli switch Nexus 7000 sono configurati con una priorità di 8192 per tutte le VLAN. L'N7K-1 vince le elezioni del bridge perché ha l'ID del bridge più basso. Pertanto, ci si aspetta che SW-1 blocchi il collegamento dalla N7K-2. SW-2 è collegato agli switch Nexus 7000 tramite un vPC e sarà in stato di inoltro. SW-2 riceve le BDPU (Bridge Protocol Data Unit) solo dallo switch primario del vPC, che in questo esempio è N7K-1.
SW-1# show span vlan 1VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 8193
Address 0024.986f.3b41
Cost 4
Port 295 (Ethernet2/39)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0024.986f.3b44
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Eth2/39 Root FWD 4 128.295 P2p
Eth2/40 Altn BLK 4 128.296 P2p
SW-1# show span vlan 1 detail
VLAN0001 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 1, address 0024.986f.3b44
Configured hello time 2, max age 20, forward delay 15
Current root has priority 8193, address 0024.986f.3b41
Root port is 295 (Ethernet2/39), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 4 last change occurred 0:29:13 ago
from Ethernet2/39
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 295 (Ethernet2/39) of VLAN0001 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.295
Designated root has priority 8193, address 0024.986f.3b41
Designated bridge has priority 8193, address 0024.986f.3b41
Designated port id is 128.260, designated path cost 0, Topology change is set
Timers: message age 16, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 4, received 898
Port 296 (Ethernet2/40) of VLAN0001 is alternate blocking
Port path cost 4, Port priority 128, Port Identifier 128.296
Designated root has priority 8193, address 0024.986f.3b41
Designated bridge has priority 8193, address 0024.986f.3b42 <-- Although same priority,
Designated port id is 128.272, designated path cost 2 advertising Bridge ID is higher
Timers: message age 16, forward delay 0, hold 0 and therefore this link is BLK
Number of transitions to forwarding state: 2
Link type is point-to-point by default
BPDU: sent 6, received 895
Questo è un diagramma di rete di una configurazione ibrida con switch peer abilitato. Quando lo switch peer è abilitato, ciascuno switch Nexus 7000 condivide un ID bridge virtuale che consente a entrambi gli switch di fungere da radice per la VLAN. Il collegamento peer vPC è sempre in stato di inoltro ed esegue il protocollo L2GIP (L2 Gateway Interconnection Protocol) per evitare loop di bridging.
Ogni switch Nexus 7000 invia pacchetti BPDU con un bridge radice identificato dall'ID del bridge virtuale. Nei collegamenti vPC, l'ID bridge designato utilizza anche l'ID bridge virtuale. Per i collegamenti non vPC, l'ID bridge designato è l'ID bridge fisico dello switch Nexus 7000 corrispondente. Ciò consente allo switch non vPC (SW-1) di prendere una decisione root in base agli annunci BPDU anziché alla priorità della porta.
Se lo switch peer è abilitato, ogni switch Nexus 7000 genera BPDU con il bridge radice impostato sull'ID del bridge virtuale e il bridge designato impostato sull'ID del bridge fisico. Poiché le priorità sono le stesse, tutte le connessioni non vPC vengono sempre inoltrate sul collegamento collegato allo switch Nexus 7000 con l'ID bridge inferiore (N7K-1 nell'esempio) e bloccate sui collegamenti collegati allo switch Nexus 7000 con l'ID bridge superiore (N7K-2 nell'esempio).
SW-1# show span vlan 1
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 8193
Address 0023.04ee.be01
Cost 4
Port 295 (Ethernet2/39)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0024.986f.3b44
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Eth2/39 Root FWD 4 128.295 P2p
Eth2/40 Altn BLK 4 128.296 P2p
SW-1# show span vlan 1 detail
VLAN0001 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 1, address 0024.986f.3b44
Configured hello time 2, max age 20, forward delay 15
Current root has priority 8193, address 0023.04ee.be01
Root port is 295 (Ethernet2/39), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 6 last change occurred 0:25:38 ago
from Ethernet2/39
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 295 (Ethernet2/39) of VLAN0001 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.295
Designated root has priority 8193, address 0023.04ee.be01 <---Root Bridge = virtual ID
Designated bridge has priority 8193, address 0024.986f.3b41 <---Designated Bridge ID = N7K-1
Designated port id is 128.260, designated path cost 0, Topology change is set
Timers: message age 16, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 4, received 2280
Port 296 (Ethernet2/40) of VLAN0001 is alternate blocking
Port path cost 4, Port priority 128, Port Identifier 128.296
Designated root has priority 8193, address 0023.04ee.be01 <---Root Bridge = virtual ID
Designated bridge has priority 8193, address 0024.986f.3b42 <---Designated Bridge ID = N7K-2
Designated port id is 128.272, designated path cost 0
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 2
Link type is point-to-point by default
BPDU: sent 7, received 2278
Con lo switch peer abilitato, le connessioni vPC ricevono BPDU con il bridge radice e il bridge designato impostati sull'ID del bridge virtuale.
SW-2# show span vlan 1
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 8193
Address 0023.04ee.be01
Cost 3
Port 4105 (port-channel10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0024.986f.3b43
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po10 Root FWD 3 128.4105 P2p
SW-2# show span vlan 1 detail
VLAN0001 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 1, address 0024.986f.3b43
Configured hello time 2, max age 20, forward delay 15
Current root has priority 8193, address 0023.04ee.be01
Root port is 4105 (port-channel10), cost of root path is 3
Topology change flag not set, detected flag not set
Number of topology changes 5 last change occurred 0:21:40 ago
from port-channel10
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 4105 (port-channel10) of VLAN0001 is root forwarding
Port path cost 3, Port priority 128, Port Identifier 128.4105
Designated root has priority 8193, address 0023.04ee.be01 <--- Virtual Bridge ID
Designated bridge has priority 8193, address 0023.04ee.be01 <--- Virtual Bridge ID
Designated port id is 128.4105, designated path cost 0, Topology change is set
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 2
Link type is point-to-point by default
BPDU: sent 96, received 2804
In base alla configurazione predefinita dello switch peer, tutte le VLAN sullo switch non vPC vengono inoltrate su un singolo collegamento. Per bilanciare il carico tra le VLAN, le priorità designate e quelle principali annunciate possono essere impostate manualmente usando le configurazioni delle pseudo informazioni dello Spanning Tree. Cisco consiglia che la priorità radice nelle pseduo-informazioni sia inferiore alla migliore priorità Spanning Tree per evitare notifiche di modifica della topologia (TCN) in condizioni di failover. È possibile bilanciare il carico delle priorità designate tra i due switch Nexus 7000 nel dominio vPC.
Nell'esempio, le priorità globali dello Spanning Tree su entrambi gli switch Nexus 7000 sono state impostate su 8192. In base alle pseudo informazioni, la priorità radice è stata configurata come 4096, che è inferiore alla priorità migliore di 8192. Pertanto, lo switch che partecipa con lo switch peer abilitato diventa la radice della VLAN. Per bilanciare il carico tra i due switch, le priorità designate vengono alternate per la VLAN 9 e la VLAN 10. Per le connessioni non vPC all'SW-1, la VLAN 9 viene inoltrata sul collegamento all'N7K-1 e la VLAN 10 sul collegamento all'N7K-2.
Per la VLAN 9, il software SW-1 considera la priorità e l'ID del bridge della pseudo radice come lo stesso valore di N7K-1 e N7K-2. Tuttavia, sia N7K-1 che N7K-2 inviano le loro pseudo priorità designate configurate. Pertanto, SW-1 vede la priorità di ponte designato di 8201 (8192 + 9) da N7K-1 e la priorità di ponte designato di 12297 (12288 + 9) da N7K-2; SW-1 sceglie il collegamento verso N7K-1 come collegamento di inoltro sulla VLAN 9.
SW-1# show span vlan 9
VLAN0009
Spanning tree enabled protocol rstp
Root ID Priority 4105
Address 0023.04ee.be01
Cost 4
Port 295 (Ethernet2/39)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32777 (priority 32768 sys-id-ext 9)
Address 0024.986f.3b44
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Eth2/39 Root FWD 4 128.295 P2p
Eth2/40 Altn BLK 4 128.296 P2p
SW-1# show span vlan 9 detail
VLAN0009 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 9, address 0024.986f.3b44
Configured hello time 2, max age 20, forward delay 15
Current root has priority 4105, address 0023.04ee.be01
Root port is 295 (Ethernet2/39), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 16 last change occurred 0:06:56 ago
from Ethernet2/39
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 295 (Ethernet2/39) of VLAN0009 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.295
Designated root has priority 4105, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 8201, address 0024.986f.3b41 <--- Designated N7K-1, 8201
Designated port id is 128.260, designated path cost 0
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
BPDU: sent 31, received 3486
Port 296 (Ethernet2/40) of VLAN0009 is alternate blocking
Port path cost 4, Port priority 128, Port Identifier 128.296
Designated root has priority 4105, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 12297, address 0024.986f.3b42 <--- Designated is N7K-2, 12297
Designated port id is 128.272, designated path cost 0
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 4
Link type is point-to-point by default
BPDU: sent 31, received 3496
Analogamente, per la VLAN 10, il software SW-1 considera la priorità e l'ID del bridge della pseudo radice come lo stesso valore di N7K-1 e N7K-2. Anche in questo caso, sia N7K-1 che N7K-2 inviano le loro pseudo priorità designate configurate. Per la VLAN 10, il software SW-1 considera la priorità del bridge designata di 12298 (12288 + 10) dall'N7K-1 e la priorità del bridge designato di 8202 (8192 + 10) dall'N7K-2; SW-1 sceglie il collegamento verso N7K-2 come collegamento di inoltro per la VLAN 10. In questo modo, gli switch connessi senza vPC possono bilanciare il carico dello stato VLAN STP tra N7K-1 e N7K-2.
SW-1# show span vlan 10 detail
VLAN0010 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 10, address 0024.986f.3b44
Configured hello time 2, max age 20, forward delay 15
Current root has priority 4106, address 0023.04ee.be01
Root port is 296 (Ethernet2/40), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 7 last change occurred 0:07:13 ago
from Ethernet2/40
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 295 (Ethernet2/39) of VLAN0010 is alternate blocking
Port path cost 4, Port priority 128, Port Identifier 128.295
Designated root has priority 4106, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 12298, address 0024.986f.3b41 <--- Designated N7K-1, 12298
Designated port id is 128.260, designated path cost 0, Topology change is set
Timers: message age 16, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 4, received 3497
Port 296 (Ethernet2/40) of VLAN0010 is root forwarding
Port path cost 4, Port priority 128, Port Identifier 128.296
Designated root has priority 4106, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 8202, address 0024.986f.3b42 <--- Designated N7K-2, 8202
Designated port id is 128.272, designated path cost 0
Timers: message age 16, forward delay 0, hold 0
Number of transitions to forwarding state: 3
Link type is point-to-point by default
BPDU: sent 10, received 3492
Per i collegamenti vPC, i campi radice e designato utilizzano rispettivamente la priorità pseudo-radice e l'ID bridge virtuale.
SW-2# show span vlan 9
VLAN0009
Spanning tree enabled protocol rstp
Root ID Priority 4105
Address 0023.04ee.be01
Cost 3
Port 4105 (port-channel10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32777 (priority 32768 sys-id-ext 9)
Address 0024.986f.3b43
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po10 Root FWD 3 128.4105 P2p
SW-2# show span vlan 10
VLAN0010
Spanning tree enabled protocol rstp
Root ID Priority 4106
Address 0023.04ee.be01
Cost 3
Port 4105 (port-channel10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 0024.986f.3b43
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po10 Root FWD 3 128.4105 P2p
SW-2#show span vlan 9 detail
VLAN0009 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 9, address 0024.986f.3b43
Configured hello time 2, max age 20, forward delay 15
Current root has priority 4105, address 0023.04ee.be01
Root port is 4105 (port-channel10), cost of root path is 3
Topology change flag not set, detected flag not set
Number of topology changes 12 last change occurred 0:04:29 ago
from port-channel10
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 4105 (port-channel10) of VLAN0009 is root forwarding
Port path cost 3, Port priority 128, Port Identifier 128.4105
Designated root has priority 4105, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 4105, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated port id is 128.4105, designated path cost 0, Topology change is set
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 2
Link type is point-to-point by default
BPDU: sent 119, received 4867
SW-2# show span vlan 10 detail
VLAN0010 is executing the rstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 10, address 0024.986f.3b43
Configured hello time 2, max age 20, forward delay 15
Current root has priority 4106, address 0023.04ee.be01
Root port is 4105 (port-channel10), cost of root path is 3
Topology change flag not set, detected flag not set
Number of topology changes 6 last change occurred 0:04:36 ago
from port-channel10
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 4105 (port-channel10) of VLAN0010 is root forwarding
Port path cost 3, Port priority 128, Port Identifier 128.4105
Designated root has priority 4106, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated bridge has priority 4106, address 0023.04ee.be01 <--- Root Virtual Bridge ID
Designated port id is 128.4105, designated path cost 0, Topology change is set
Timers: message age 17, forward delay 0, hold 0
Number of transitions to forwarding state: 2
Link type is point-to-point by default
BPDU: sent 96, received 5179
Vedere l'ID bug Cisco CSCub74914: Le priorità Pseudo STP non sono impostate correttamente sui collegamenti vPC nella configurazione dello switch peer
Attualmente non è disponibile una procedura di verifica per questa configurazione.
Al momento non sono disponibili informazioni specifiche per la risoluzione dei problemi di questa configurazione.
Revisione | Data di pubblicazione | Commenti |
---|---|---|
1.0 |
09-Aug-2013 |
Versione iniziale |