Clever Geek Handbook

Implementación de VPN de multidifusión en Cisco IOS (Parte 1)

Al comprender los métodos modernos de organización de VPN de multidifusión, noté que no hay mucho material en la red que describa los principios y detalles de la tecnología. El sitio web del proveedor proporciona una configuración suficiente para la implementación, pero no describe el significado de todas las acciones realizadas.



En esta serie de artículos, intentaré abrir el misterio de cómo funciona todo bajo el capó.



Aprox. El autor asume que el lector está familiarizado con las siguientes tecnologías: OSPF, BGP, PIM, MPLS.



Interesado - bienvenido bajo gato.



La tarea principal es tunelizar paquetes de multidifusión entre enrutadores PE (desde Ingress PE a uno o más Egress PE). Esto requiere construir una red superpuesta sobre la infraestructura subyacente.



Si pasamos a RFC6513, encontraremos una explicación bastante espacial sobre cómo se debe transmitir el tráfico entre los enrutadores PE: “Deben usarse túneles P: un túnel P es un mecanismo de transporte dentro de la red del proveedor de servicios que crea una instancia una interfaz de servicio de multidifusión de proveedor (PMSI). Un PMSI es una "superposición" conceptual en la red P con la siguiente propiedad: un PE en un MVPN dado puede entregar un paquete al PMSI, y el paquete se entregará a algunos o todos los demás PE en el MVPN, de modo que cualquier PE que reciba el paquete podrá determinar el MVPN al que pertenece el paquete ".



Aquellos. Si simplemente sigue lo que se dijo, toda la infraestructura de VPN de multidifusión se verá así:





Lo único que queda es descubrir cómo construir este PMSI y cómo los dispositivos PE pueden aprender unos de otros.



-:



  • Protocol Independent Multicast (PIM, P-PIM, Provider-PIM; PIM GRT)
  • Multipoint Label Distribution Protocol (mLDP)
  • Resource Reservation Protocol Traffic Engineering (RSVP-TE)
  • Ingress Replication (IR)


. PMSI PIM mLDP.



-, / . :



  • PIM (C-PIM, Customer-PIM; PIM (VRF))
  • BGP.


mVPN :



  • . (C-Multicast) .




, .



, , :



  • - (Point-to-Point)

    • ( , MPLS ), LSP (unicast) .
  • - (Point-to-Multipoint)

    • ( , root) . (unidirectional).
  • - (Multipoint-to-Multipoint)

    • (bidirectional), , . , .
  • -- (Point-to-Point-to-Multipoint)

    • P2P P2MP . P2P LSP , P2MP .

      , Partitioned MDT.


:



  • Multi-Directional Inclusive PMSI (MI-PMSI, aka Default MDT)
  • Selective PMSI (aka Data MDT)
  • Multi-Directional Selective PMSI (aka Partitioned MDT)


( ). , mVPN «Default MDT».



Default MDT



Default MDT PE- VPN (VRF) . Default MDT , PIM .



Default MDT - PE PIM VRF, PIM (Join/Prune, RPT Switchover) Default MDT , LAN .





mVPN Profile 0



mVPN «Profile 0», «Draft Rosen».



:



  • Default MDT
  • PIM
  • PIM
  • C-multicast GRE (mGRE )


, , . :



  • BGP ( , VPNv4), unicast RPF .
  • OSPF IS-IS ( ) IP- Loopback0 , BGP
  • PIM ASM ( Global Routing Table, GRT)

    • Bootstrap Router (BSR)
  • LDP / .


:



router ospf 1
 router-id X.X.X.X
!
ip mutlicast-routing
!
ip pim register-source Lo0
!
interface Loopback0
 ip address X.X.X.X 255.255.255.255
 ip ospf 1 area 0
 ip pim sparse-mode
!
interface Gi2.Y
 encapsulation dot1q Y
 ip address 10.X.Y.Z 255.255.255.0
 ip ospf 1 area 0
 ip pim sparse-mode
!
router bgp 65001
 bgp router-id X.X.X.X
 no bgp default ipv4 unicast
 neighbor Y.Y.Y.Y remote-as 65001
 neighbor Y.Y.Y.Y update-source Loopback0
 !
 address-family vpnv4
  neighbor Y.Y.Y.Y activate
  neighbor Y.Y.Y.Y send-community-both
!
#############################################
##########     ##########
#############################################
!
ip pim rp-candidate Lo0
ip pim bsr-candidate Lo0


, , ( Provider RP (P-RP) – ). , show ip int brief. ? : Tunnel (encap) PIM-Register P-RP. P-RP Tunnel (decap) Register .



. 



PE1#show int tu2 | i Descr|destination|Tunnel2
Tunnel2 is up, line protocol is up 
  Description: **Pim Register Tunnel (Encap)** for RP 8.8.8.8
  Tunnel source 1.1.1.1 (Loopback0), destination 8.8.8.8


>RR#show int tu0 | i Descr|destination|Tunnel0
Tunnel0 is up, line protocol is up 
  Description: **Pim Register Tunnel (Encap)** for RP 8.8.8.8
  Tunnel source 8.8.8.8 (Loopback0), destination 8.8.8.8
         Tunnel0 source tracking subblock associated with Loopback0
RR#show int tu1 | i Descr|destination|Tunnel1
Tunnel1 is up, line protocol is up 
  Description: Pim Register Tunnel (**Decap**) for RP 8.8.8.8
  Tunnel source 8.8.8.8 (Loopback0), destination 8.8.8.8
         Tunnel1 source tracking subblock associated with Loopback0


Profile 0 C-multicast mGRE . () IP . ( GRT). PIM GRT. :



ip vrf C-ONE
 mdt default 239.1.1.1


, ingress PE - VRF, ingress mGRE, destination IP 239.1.1.1 .



, egress PE . . .



PE2#show ip igmp membership 
Flags: A  - aggregate, T - tracked
       L  - Local, S - static, V - virtual, R - Reported through v3 
       I - v3lite, U - Urd, M - SSM (S,G) channel 
       1,2,3 - The version of IGMP, the group is in
Channel/Group-Flags: 
       / - Filtering entry (Exclude mode (S,G), Include mode (G))
Reporter:
       <mac-or-ip-address> - last reporter if group is not explicitly tracked
       <n>/<m>      - <n> reporter in include mode, <m> reporter in exclude

 Channel/Group                  Reporter        Uptime   Exp.  Flags  Interface 
 *,239.1.1.1                    2.2.2.2         1d20h    stop  2VA    Lo0


, 2 (*, 239.1.1.1) Loopback0. , , PIM Join RP .



, 2 mRIB. PIM ASM (shared tree source-based tree):



P2#show ip mroute 239.1.1.1
IP Multicast Routing Table

(*, 239.1.1.1), 2d00h/00:03:09, RP 8.8.8.8, flags: S
  Incoming interface: GigabitEthernet2.68, RPF nbr 10.6.8.8
  Outgoing interface list:
    GigabitEthernet2.67, Forward/Sparse, 2d00h/00:03:09
    GigabitEthernet2.26, Forward/Sparse, 2d00h/00:03:05
 (2.2.2.2, 239.1.1.1), 05:22:26/00:01:55, flags: T
  Incoming interface: GigabitEthernet2.26, RPF nbr 10.2.6.2
  Outgoing interface list:
    GigabitEthernet2.56, Forward/Sparse, 05:22:26/00:02:46
    GigabitEthernet2.67, Forward/Sparse, 05:22:26/00:03:09


, MDT vrf C-ONE , :



P2#show ip mroute 239.1.1.1
IP Multicast Routing Table
(*, 239.1.1.1), 2d00h/00:03:09, RP 8.8.8.8, flags: S
  Incoming interface: GigabitEthernet2.68, RPF nbr 10.6.8.8
  Outgoing interface list:
    GigabitEthernet2.67, Forward/Sparse, 2d00h/00:03:09
    GigabitEthernet2.26, Forward/Sparse, 2d00h/00:03:05

(4.4.4.4, 239.1.1.1), 05:21:57/00:02:16, flags: T
  Incoming interface: GigabitEthernet2.56, RPF nbr 10.5.6.5
  Outgoing interface list:
    GigabitEthernet2.26, Forward/Sparse, 05:21:57/00:03:15

(3.3.3.3, 239.1.1.1), 05:22:22/00:01:46, flags: T
  Incoming interface: GigabitEthernet2.67, RPF nbr 10.6.7.7
  Outgoing interface list:
    GigabitEthernet2.26, Forward/Sparse, 05:22:22/00:03:05

(2.2.2.2, 239.1.1.1), 05:22:26/00:01:55, flags: T
  Incoming interface: GigabitEthernet2.26, RPF nbr 10.2.6.2
  Outgoing interface list:
    GigabitEthernet2.56, Forward/Sparse, 05:22:26/00:02:46
    GigabitEthernet2.67, Forward/Sparse, 05:22:26/00:03:09

(1.1.1.1, 239.1.1.1), 2d00h/00:03:15, flags: T
  Incoming interface: GigabitEthernet2.56, RPF nbr 10.5.6.5
  Outgoing interface list:
    GigabitEthernet2.26, Forward/Sparse, 2d00h/00:03:05


GRT. ? — C-VRF! .



PMSI. Cisco IOS ( Profile 0) MDT BGP. MDT , PMSI .



MDT Route Reflector (R8).



PE1#sh run | s bgp
router bgp 65001
 !
 address-family ipv4 mdt
  neighbor 8.8.8.8 activate
 exit-address-family


Tunnel:



*Nov 12 11:27:45.131: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0, changed state to up


PE1#show int Tu0 | i transport|source|Tunnel0
Tunnel0 is up, line protocol is up 
  Tunnel source 1.1.1.1 (Loopback0)
         Tunnel0 source tracking subblock associated with Loopback0
          Set of tunnels with source Loopback0, 2 members (includes iterators), on interface <OK>
  Tunnel protocol/transport multi-GRE/IP
  Tunnel transport MTU 1476 bytes


Tunnel0 — , PMSI C-VRF.



PE1#show ip pim vrf C-ONE interface 

Address          Interface                Ver/   Nbr    Query  DR         DR
                                          Mode   Count  Intvl  Prior
172.1.11.1       GigabitEthernet2.111     v2/S   1      30     1          172.1.11.11
172.1.15.1       GigabitEthernet2.115     v2/S   1      30     1          172.1.15.15
1.1.1.1          Tunnel0                  v2/S   3      30     1          4.4.4.4


PIM Hello ( 224.0.0.13) , VRF Default MDT.



PE1#show ip pim vrf C-ONE interface 
Address          Interface                Ver/   Nbr    Query  DR         DR
                                          Mode   Count  Intvl  Prior
172.1.11.1       GigabitEthernet2.111     v2/S   1      30     1          172.1.11.11
172.1.15.1       GigabitEthernet2.115     v2/S   1      30     1          172.1.15.15
1.1.1.1          Tunnel0                  v2/S   3      30     1          4.4.4.4


PE1#show ip pim vrf C-ONE neighbor           
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      P - Proxy Capable, S - State Refresh Capable, G - GenID Capable,
      L - DR Load-balancing Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
172.1.11.11       GigabitEthernet2.111     4d20h/00:01:25    v2    1 / DR S P G
172.1.15.15       GigabitEthernet2.115     4d21h/00:01:25    v2    1 / DR S P G
3.3.3.3           Tunnel0                  00:07:25/00:01:41 v2    1 / S P G
2.2.2.2           Tunnel0                  00:07:25/00:01:41 v2    1 / S P G
4.4.4.4           Tunnel0                  00:08:24/00:01:41 v2    1 / DR S P G


PIM Hello, 1. , ( VRF) IP-, .







, Default MDT Multipoint-to-Multipoint .. (. PIM Hello) , .



: « MDT? PIM ASM ».



, Cisco IOS , PMSI BGP . , (Tunnel0 UP neighbor activate).



MDT , PIM SSM. , RP, - . MDT :



PE1#show bgp ipv4 mdt all 
     Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 1.1.1.1:1 (default for vrf C-ONE)
 *>   1.1.1.1/32       0.0.0.0                                0 ?
Route Distinguisher: 2.2.2.2:1
 *>i  2.2.2.2/32       2.2.2.2                  0    100      0 ?
Route Distinguisher: 3.3.3.3:1
 *>i  3.3.3.3/32       3.3.3.3                  0    100      0 ?
Route Distinguisher: 4.4.4.4:1
 *>i  4.4.4.4/32       4.4.4.4                  0    100      0 ?


PE1#show bgp ipv4 mdt all 2.2.2.2/32
BGP routing table entry for 2.2.2.2:1:2.2.2.2/32         version 3
Paths: (1 available, best #1, table IPv4-MDT-BGP-Table)
  Not advertised to any peer
  Refresh Epoch 1
  Local
    2.2.2.2 from 8.8.8.8 (8.8.8.8)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Originator: 2.2.2.2, Cluster list: 8.8.8.8,
      MDT group address: 239.1.1.1

      rx pathid: 0, tx pathid: 0x0


Originator MDT group address, (S,G) .



. : The Address Family (AF) IPv4 Multicast Distribution Tree (MDT) must be used for all types of PIM signaling in the core (not only for PIM Source Specific Multicast (SSM)).

.. sAFI MDT , .



.



, CE3 CE4 :



interface Loopback0
 ip igmp join-group 230.0.0.1


, 3 4 :



PE3#show ip mroute vrf C-ONE       

(*, 230.0.0.1), 05:58:36/00:03:19, RP 15.15.15.15, flags: S
  Incoming interface: Tunnel1, RPF nbr 1.1.1.1
  Outgoing interface list:
    GigabitEthernet2.313, Forward/Sparse, 00:00:10/00:03:19


PE4#show ip mroute vrf C-ONE

(*, 230.0.0.1), 00:00:29/00:03:00, RP 15.15.15.15, flags: S
  Incoming interface: Tunnel0, RPF nbr 1.1.1.1
  Outgoing interface list:
    GigabitEthernet2.414, Forward/Sparse, 00:00:29/00:03:00


2 OIL ( ). , IIL Tunnel (default MDT). .. 2 230.0.0.1 .



PE2#show ip mroute 239.1.1.1

(*, 239.1.1.1), 05:06:26/stopped, RP 8.8.8.8, flags: SJCFZ
  Incoming interface: GigabitEthernet2.26, RPF nbr 10.2.6.6
  Outgoing interface list:
    MVRF C-ONE, Forward/Sparse, 05:06:26/stopped


PE2#show ip mroute vrf C-ONE

(*, 230.0.0.1), 05:59:17/00:01:08, RP 15.15.15.15, flags: SP
  Incoming interface: Tunnel1, RPF nbr 1.1.1.1
  Outgoing interface list: Null


:



CE1#ping 230.0.0.1 source 11.11.11.11
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 230.0.0.1, timeout is 2 seconds:
Packet sent with a source address of 11.11.11.11 

Reply to request 0 from 14.14.14.14, 11 ms
Reply to request 0 from 13.13.13.13, 13 ms


, , PIM ( mGRE):





: MPLS , ( Profile 0) .



(ICMP reply) MPLS L3 VPN:





, Default MDT . , PE-, , C-Receiver . , ​​ PE, . ( VLAN ID = 26, R2 (PE2) R6 (P2)).







Para eludir las limitaciones de Default MDT, se introduce el concepto de Data MDT, que permite cambiar el tráfico de usuario C- (S, G) de Default MDT a Data MDT, en el que solo están involucrados aquellos PE donde hay fuentes activas o receptores de tráfico. Hablaremos de esto con usted en el próximo número.



Continuará...



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