Introduzione
In questo documento viene descritto come configurare e verificare la funzione Service Reflection sugli switch Cisco Nexus serie 3000 (modalità regolare).
Prerequisiti
Requisiti
Suggerimenti generali per la conoscenza dei seguenti argomenti:
- PIM (Protocol Independent Multicast)
- OSPF (Open Shortest Path First)
- NAT (Network Address Translation)
- Protocollo IGMP (Internet Group Management Protocol)
Componenti usati
Le informazioni fornite in questo documento si basano sulle seguenti versioni software e hardware:
| N. software |
N9K-C93180YC-FX |
NXOS: versione 9.3(5) |
| N. software |
N3K-C3548P-XL |
NXOS: versione 7.0(3)I7(9) |
| N. software |
N3K-C3172TQ-10GT |
NXOS: versione 7.0(3)I7(9) |
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.
Premesse
Piattaforme Cisco Nexus 3k supportate
La funzione multicast service reflection è supportata solo sulle piattaforme Cisco Nexus 3548-X dalla versione 7.0(3)I7(2).
Riflessione sui metodi di servizio supportati
Multicast NAT in modalità regolare
In modalità normale, i pacchetti in entrata come interfacce S1, G1 vengono convertiti in interfacce S2, G2 e l'indirizzo MAC (Media Access Control) di destinazione del pacchetto in uscita viene convertito come indirizzo MAC multicast dell'interfaccia G2 (ad esempio, il gruppo tradotto).
Fast-pass e Fast-pass con NAT multicast senza riscrittura
In modalità fast-pass, le interfacce S1, G1 vengono convertite in interfacce S2, G2 e l'indirizzo MAC di destinazione del pacchetto in uscita ha l'indirizzo MAC multicast che corrisponde all'interfaccia G1 (ad esempio, l'indirizzo MAC del gruppo pre-tradotto).
Configurazione
Topologia

Gruppo nativo: 239.194.169.1 (G1)
Gruppo tradotto: 233.193.40.196 (G2)
Fonte originale: 10.11.11.1 (S1)
Fonte tradotta: 172.16.0.1. (S2)
Configurazione
Configurazione switch 1 (mittente)
SW1# show run int eth1/47
interface Ethernet1/47
no switchport
ip address 10.11.11.1/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
SW1# show run ospf
feature ospf
router ospf 1
router-id 192.168.1.1
interface Ethernet1/47
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
SW1# show run pim
feature pim
ip pim rp-address 10.10.10.10 group-list 239.194.169.1/32
ip pim ssm range 232.0.0.0/8
interface Ethernet1/47
ip pim sparse-mode
Configurazione switch 2 (convertitore)
SW2# show run int eth 1/23,eth1/47
interface Ethernet1/23
no switchport
ip address 10.0.0.1/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
no shutdown
interface Ethernet1/47
no switchport
ip address 10.11.11.2/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
no shutdown
SW2# show run int lo0,lo411
interface loopback0
ip address 10.10.10.10/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
interface loopback411
ip address 172.16.0.1/32
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
ip igmp join-group 239.194.169.1
SW2# show run ospf
feature ospf
router ospf 1
router-id 192.168.1.2
interface loopback0
ip router ospf 1 area 0.0.0.0
interface loopback411
ip router ospf 1 area 0.0.0.0
interface Ethernet1/23
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
interface Ethernet1/47
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
SW2# show run pim
feature pim
ip pim rp-address 10.10.10.10 group-list 239.194.169.1/32
ip pim rp-address 172.16.0.1 group-list 233.193.40.196/32
ip pim ssm range 232.0.0.0/8
interface loopback0
ip pim sparse-mode
interface loopback411
ip pim sparse-mode
interface Ethernet1/23
ip pim sparse-mode
interface Ethernet1/47
ip pim sparse-mode
ip service-reflect mode regular
ip service-reflect destination 239.194.169.1 to 233.193.40.196 mask-len 32 source 172.16.0.1
hardware profile multicast service-reflect port 7
Configurazione switch 3 (ricevitore)
SW3# show run int eth 1/24
interface Ethernet1/24
ip address 10.0.0.2/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
ip igmp join-group 233.193.40.196
no shutdown
SW3# show run ospf
feature ospf
router ospf 1
router-id 192.168.1.3
interface Ethernet1/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
SW3# show run pim
feature pim
ip pim rp-address 172.16.0.1 group-list 233.193.40.196/32
ip pim ssm range 232.0.0.0/8
interface Ethernet1/24
ip pim sparse-mode
Verifica
Fare riferimento a questa sezione per verificare che la configurazione funzioni correttamente.
Verifica funzionalità di Service Reflection
Verifica switch 1
SW1# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 3w6d, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(10.11.11.1/32, 239.194.169.1/32), uptime: 00:06:57, pim ip
Incoming interface: Ethernet1/47, RPF nbr: 10.11.11.1
Outgoing interface list: (count: 1)
Ethernet1/47, uptime: 00:06:57, pim, (RPF)
Verifica switch 2
SW2# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 00:04:39, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 233.193.40.196/32), uptime: 00:04:11, pim ip
Incoming interface: loopback411, RPF nbr: 172.16.0.1 <-- Translation (ingress) Loopback interface
Outgoing interface list: (count: 1)
Ethernet1/23, uptime: 00:03:59, pim <-- Egress interface for S2,G2
(172.16.0.1/32, 233.193.40.196/32), uptime: 00:00:15, ip mrib pim
Incoming interface: loopback411, RPF nbr: 172.16.0.1
Outgoing interface list: (count: 1)
Ethernet1/23, uptime: 00:00:15, pim
(*, 239.194.169.1/32), uptime: 00:04:34, static pim ip <-- (The NAT router would pull the traffic by using a (*,G) join on loopback )
Incoming interface: loopback0, RPF nbr: 10.10.10.10
Outgoing interface list: (count: 1)
loopback411, uptime: 00:04:34, static <-- Translation (egress) Loopback interface
(10.11.11.1/32, 239.194.169.1/32), uptime: 00:00:17, ip mrib pim
Incoming interface: Ethernet1/47, RPF nbr: 10.11.11.1, internal <-- Ingress interface for S1,G1
Outgoing interface list: (count: 1)
loopback411, uptime: 00:00:17, mrib
SW2# show ip mroute sr <-- (Only SR nat routes)
IP Multicast Routing Table for VRF "default"
(*, 239.194.169.1/32), uptime: 00:09:29, static pim ip
NAT Mode: Ingress
NAT Route Type: Pre
Incoming interface: loopback0, RPF nbr: 10.10.10.10
Translation list: (count: 1)
SR: (172.16.0.1, 233.193.40.196)
(10.11.11.1/32, 239.194.169.1/32), uptime: 00:05:12, ip mrib pim
NAT Mode: Ingress
NAT Route Type: Pre
Incoming interface: Ethernet1/47, RPF nbr: 10.11.11.1, internal
Translation list: (count: 1)
SR: (172.16.0.1, 233.193.40.196)
Verifica switch 3
SW3# show ip mroute
IP Multicast Routing Table for VRF "default"
(*, 232.0.0.0/8), uptime: 02:45:09, pim ip
Incoming interface: Null, RPF nbr: 0.0.0.0
Outgoing interface list: (count: 0)
(*, 233.193.40.196/32), uptime: 01:47:02, ip pim igmp
Incoming interface: Ethernet1/24, RPF nbr: 10.0.0.1
Outgoing interface list: (count: 1)
Ethernet1/24, uptime: 01:43:27, igmp, (RPF)
(172.16.0.1/32, 233.193.40.196/32), uptime: 00:02:59, ip mrib pim
Incoming interface: Ethernet1/24, RPF nbr: 10.0.0.1
Outgoing interface list: (count: 1)
Ethernet1/24, uptime: 00:02:59, mrib, (RPF)
Risoluzione dei problemi
Le informazioni contenute in questa sezione permettono di risolvere i problemi relativi alla configurazione.
Se S2 e G2 non vengono creati o l'utente deve affrontare problemi di traduzione casuali, è possibile controllare i seguenti punti:
1. Una volta ricevuto il traffico (pre-tradotto), le voci post-tradotte vengono create in base al pkt puntato in mcastfwd.
2. Se il comando pkt non viene visualizzato in mcastfwd, è possibile controllare se il traffico richiesto si trova sull'interfaccia in entrata tramite ACL.
3 Se vengono visualizzati più contatori nell'ACL, verificare che lo stesso traffico raggiunga la CPU tramite l'analizzatore.
4 Può anche controllare la traduzione nella cronologia degli eventi MRIB:
SW2# show system internal mfwd ip mroute --> Packets Punted in Mcast Forwarding.
MCASTFWD Multicast Routing Table for VRF "default"
(0.0.0.0/0, 232.0.0.0/8)
Software switched packets: 0, bytes: 0
RPF fail packets: 0, bytes: 0
(0.0.0.0/0, 233.193.40.196/32)
Software switched packets: 1, bytes: 84
RPF fail packets: 0, bytes: 0
(172.16.0.1/32, 233.193.40.196/32), data-alive
Software switched packets: 1, bytes: 84
RPF fail packets: 8, bytes: 672
(0.0.0.0/0, 239.194.169.1/32)
Software switched packets: 1, bytes: 84
RPF fail packets: 0, bytes: 0
(10.11.11.1/32, 239.194.169.1/32), data-alive
Software switched packets: 10, bytes: 840
RPF fail packets: 0, bytes: 0
SW2# show ip access-lists test
IP access list test
statistics per-entry
10 permit ip any 239.194.169.1/32 [match=105] <-- Intrested traffic hitting ingress interface
20 permit ip any any [match=11]
interface Ethernet1/47
no switchport
ip access-group test in <-- ACL applied on ingress interface
ip address 10.11.11.2/24
ip ospf network point-to-point
ip router ospf 1 area 0.0.0.0
ip pim sparse-mode
no shutdown
SW2# ethanalyzer loca int inband display-filter "ip.addr == 239.194.169.1" limit-captured-frames 0 --> Confirm (S1,G1) seen on CPU
Capturing on inband
wireshark-cisco-mtc-dissector: ethertype=0xde09, devicetype=0x0
2022-09-18 04:21:37.840227 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
2022-09-18 04:21:37.841275 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
2022-09-18 04:21:37.860153 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
2022-09-18 04:21:37.861199 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
2022-09-18 04:21:37.880072 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
2022-09-18 04:21:37.881113 10.11.11.1 -> 239.194.169.1 ICMP Echo (ping) request
SW2# ethanalyzer local interface inband capture-filter "host 172.16.0.1" limit-captured-frames 0 --> Confirm (S2,G2) seen on CPU
Capturing on inband
wireshark-cisco-mtc-dissector: ethertype=0xde09, devicetype=0x0
2022-09-18 03:12:51.423484 172.16.0.1 -> 233.193.40.196 ICMP Echo (ping) request
2022-09-18 03:12:51.423978 10.0.0.2 -> 172.16.0.1 ICMP Echo (ping) reply
2022-09-18 03:12:53.425754 172.16.0.1 -> 233.193.40.196 ICMP Echo (ping) request
2022-09-18 03:12:53.425761 10.0.0.2 -> 172.16.0.1 ICMP Echo (ping) reply
2022-09-18 03:12:55.426719 172.16.0.1 -> 233.193.40.196 ICMP Echo (ping) request
2022-09-18 03:12:55.426726 10.0.0.2 -> 172.16.0.1 ICMP Echo (ping) reply
2022-09-18 03:12:57.428669 172.16.0.1 -> 233.193.40.196 ICMP Echo (ping) request
2022-09-18 03:12:57.429175 10.0.0.2 -> 172.16.0.1 ICMP Echo (ping) reply
2022-09-18 03:12:59.429890 172.16.0.1 -> 233.193.40.196 ICMP Echo (ping) request
2022-09-18 03:12:59.430386 10.0.0.2 -> 172.16.0.1 ICMP Echo (ping) reply
10 packets captured
SW2# show ip pim event-history mrib --> Event history to confirm that the translation is being done
2022 Sep 18 04:28:39.970688: E_DEBUG pim [19433]: Sending ack: xid: 0xeeee00d2
2022 Sep 18 04:28:39.970255: E_DEBUG pim [19433]: MRIB Join notify for (10.11.11.1/32, 239.194.169.1/32)
2022 Sep 18 04:28:39.968875: E_DEBUG pim [19433]: MRIB sr route type notif for (10.11.11.1/32, 239.194.169.1/32) : 1
2022 Sep 18 04:28:39.968859: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: MRIB RPF notify for (10.11.11.1/32, 239.194.169.1/32), old RPF info: 10.11.11.1 (Ethernet1/47), new RPF info: 10.11.11.1 (Ethernet1/47). LISP source RLOC address
: 0.0.0.0, route-type 1
2022 Sep 18 04:28:39.968307: E_DEBUG pim [19433]: Copied the flags from MRIB for route (10.11.11.1/32, 239.194.169.1/32), (before/after): att F/F, sta F/F, z-oifs T/F, ext F/F, fabric F/F, fabric_src: F/F mofrr F/F
2022 Sep 18 04:28:39.968301: E_DEBUG pim [19433]: MRIB Join notify for (10.11.11.1/32, 239.194.169.1/32)
2022 Sep 18 04:28:39.968294: E_DEBUG pim [19433]: Received a notify message from MRIB xid: 0xeeee00cf for 1 mroutes
2022 Sep 18 04:28:35.904652: E_DEBUG pim [19433]: Sending ack: xid: 0xeeee00cc
2022 Sep 18 04:28:35.904625: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: MRIB RPF notify for (172.16.0.1/32, 233.193.40.196/32), old RPF info: 172.16.0.1 (loopback411), new RPF info: 172.16.0.1 (loopback411). LISP sourc
e RLOC address: 0.0.0.0, route-type 0
2022 Sep 18 04:28:35.904484: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: After copying the values for route (0.0.0.0/32, 233.193.40.196/32) we got RPF info: 172.16.0.1 (loopback411). LISP source RLOC address: 0.0.0.0, route-t
ype 0
2022 Sep 18 04:28:35.904476: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: MRIB RPF notify for (0.0.0.0/32, 233.193.40.196/32), old RPF info: 0.0.0.0 ((null)), new RPF info: 172.16.0.1 (loopback411). LISP source RLOC address: 0
.0.0.0, route-type 0
2022 Sep 18 04:28:35.904400: E_DEBUG pim [19433]: MRIB Join notify for (172.16.0.1/32, 233.193.40.196/32)
2022 Sep 18 04:28:35.904343: E_DEBUG pim [19433]: MRIB Join notify for (0.0.0.0/32, 233.193.40.196/32)
2022 Sep 18 04:27:49.862827: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: After copying the values for route (*, 239.194.169.1/32) we got RPF info: 10.10.10.10 (loopback0). LISP source RLOC address: 0.0.0.0, route-type 0
2022 Sep 18 04:27:49.862812: E_DEBUG pim [19433]: pim_process_mrib_rpf_notify: MRIB RPF notify for (*, 239.194.169.1/32), old RPF info: 0.0.0.0 ((null)), new RPF info: 10.10.10.10 (loopback0). LISP source RLOC address: 0.0.0.0, route-
type 0
2022 Sep 18 04:27:49.862798: E_DEBUG pim [19433]: MRIB Join notify for (*, 239.194.169.1/32)
2022 Sep 18 04:27:49.862795: E_DEBUG pim [19433]: MRIB Join notify for (172.16.0.1/32, 233.193.40.196/32)
2022 Sep 18 04:27:49.862789: E_DEBUG pim [19433]: MRIB Join notify for (0.0.0.0/32, 233.193.40.196/32)
2022 Sep 18 04:27:49.861870: E_DEBUG pim [19433]: Creating PIM route for (*, 239.194.169.1/32)
2022 Sep 18 04:27:49.861868: E_DEBUG pim [19433]: MRIB Join notify for (*, 239.194.169.1/32)
Riepilogo
- In modalità Normale, il traffico raggiunge la voce S, G originale al primo passaggio e circola nuovamente a causa dell'OIFL (Outgoing Interface List) che ha solo la porta di loopback. Nel secondo passaggio, deriva l'indirizzo MAC di destinazione per la riscrittura.
- Nel terzo passaggio, la ricerca della route multicast viene eseguita sui pacchetti S, G convertiti e il pacchetto viene inoltrato alle porte IFL del gruppo tradotto corrispondenti.
- È stato aggiunto un join statico al loopback per forzare la ricezione del traffico sulla casella NAT.
- Quando si riceve il primo pacchetto per (s1, g1), lo switch esegue il programma (s1,g1) con il nuovo flag SR (s1, g —> s2 ,g2).
- Lo switch userebbe questi metadati per fare il recircle del pacchetto e punt il pacchetto per g2. Una volta che il pacchetto (S2, G2) è terminato per sup, la funzionalità FHR (primo hop router) viene attivata sulla scatola NAT per s2,g2.
- Una volta ricevuto il traffico, vale a dire le voci pre-tradotte e post-tradotte verrebbero create in base al pkt punted in mcastfwd.
- Se il pacchetto non viene reindirizzato al gruppo mcastfwd corrispondente, è possibile usare la procedura di risoluzione dei problemi descritta sopra per verificare se il traffico interessato ha raggiunto lo switch
Informazioni correlate
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