ALU 7750 SR L3VPN (VPRN)

MPLS L3 VPN – the Alcatel-Lucent way of implementation

This exercise shows the Alcatel-lucent’s way of implementing MPLS L3 VPN which is named as Virtual Private Routing Network – VPRN. In this technology the PE router keeps separate virtual route-table (VRF) for each customer. VPRN uses two type of MPLS labels: outer label also called transport label, inner label called customer/service label. Customer routes are exchanged between PE using MP-BGP address family VPN-IPv4. PE can run any dynamic or static routing protocol with the CE. Here we used OSPF for PE-CE routing.

Figure: Network diagram

Router	Interface	IP Address
R1	system	50.50.50.1
	ToR2 (port 1/1/1)	192.168.12.1
	ToR4 (port 1/1/2) (vrf ABC)	10.10.10.1
R2	system	50.50.50.2
	ToR1 (port 1/1/1)	192.168.12.2
	ToR3 (port 1/1/2)	192.168.23.2
R3	system	50.50.50.3
	ToR2 (port 1/1/2)	192.168.23.3
	ToR5 (port 1/1/1) (vrf ABC)	20.20.20.1
R4	E0/0	10.10.10.2
	Loopback 1	4.4.4.4
R5	E0/0	20.20.20.2
	Loopback 1	5.5.5.5

                                                   
Table: Interface details

Step 1: IGP and MPLS

First we have to prepare the MPLS and IGP of the service provider core. In this exercise we will use ISIS as IGP and LDP for MPLS label distribution.

ISIS Configuration

R1	R2	R3
configure  router isis level-capability level-2        area-id 49.0000        level 2            wide-metrics-only        exit        interface "system"        interface "ToR2"        no shutdown	configure  router isis level-capability level-2        area-id 49.0000        level 2            wide-metrics-only        exit        interface "system"        interface "ToR1"        interface "ToR3"        no shutdown	configure  router isis level-capability level-2        area-id 49.0000        level 2            wide-metrics-only        exit        interface "system"        interface "ToR2"        no shutdown

ISIS Verification

A:R2# show router isis adjacency =============================================================================== Router Base ISIS Instance 0 Adjacency =============================================================================== System ID                Usage State Hold Interface                     MT-ID ------------------------------------------------------------------------------- R1                       L2    Up    23   ToR1                          0 R3                       L2    Up    7    ToR3                          0 ------------------------------------------------------------------------------- Adjacencies : 2 ===============================================================================

LDP Configuration

R1	R2	R3
configure  router ldp        interface-parameters                interface "ToR2"                exit	configure  router ldp        interface-parameters                interface "ToR1"                interface "ToR3"                exit	configure  router ldp        interface-parameters                interface "ToR2"                exit

*By default LDP will only create labels for system address. For other prefixes a policy statement has to be defined and exported in LDP

LDP Verification

A:R2# show router ldp peer =============================================================================== LDP Peers =============================================================================== Peer              Adm  Opr  Hello   Hold    KA      KA       Passive   Auto                            Factor  Time    Factor  Timeout  Mode      Created ------------------------------------------------------------------------------- 50.50.50.1        Up   Up   3       45      4       40       Disabled  Yes 50.50.50.3        Up   Up   3       45      4       40       Disabled  Yes ------------------------------------------------------------------------------- No. of Peers: 2 ===============================================================================

Step 2: MP-BGP

MP-BGP peering needs to be configured between the PE routers to exchange customer routes. BGP address family has to be declared as vpn-ipv4.

R1	R3
configure router autonomous-system 65000 configure router bgp           group "SP1"                family vpn-ipv4                peer-as 65000                neighbor 50.50.50.3                    next-hop-self                exit            exit            no shutdown	configure router autonomous-system 65000 configure router bgp           group "SP1"                family vpn-ipv4                peer-as 65000                neighbor 50.50.50.1                    next-hop-self                exit            exit            no shutdown

MP-BGP verification

A:R3# show router bgp summary ….output omitted…. =============================================================================== BGP Summary =============================================================================== Neighbor                   AS PktRcvd InQ  Up/Down   State|Rcv/Act/Sent (Addr Family)                      PktSent OutQ ------------------------------------------------------------------------------- 50.50.50.1                65000      39    0 00h01m34s Active                           10    0 -------------------------------------------------------------------------------

Step 3: VPRN Service

VPRN service configuration steps basically involve:

1. Creation of customer
2. Creation of vprn service
3. Add route-distinguisher
4. Add interface and assign sap, ip address
5. Add route-target bgp community

Refer to ALU Service model concept here.
Route distinguisher is the additional string (64bit) added to the IP prefixes which makes them unique and used to separate customer routes. Refer to RFC 4364.
On the other hand, Route-target is a BGP extended community used to share the routes over MP-BGP by export and import. Refer to RFC 4360.

Service VPRN configuration

R1	R3
configure service customer 100 create configure service vprn 20 customer 100 create               route-distinguisher 65000:100            auto-bind ldp            vrf-target target:65000:20            interface "ABC" create                address 10.10.10.1/24                sap 1/1/2 create                exit            exit	configure service customer 100 create configure service vprn 20 customer 100 create               route-distinguisher 65000:100            auto-bind ldp            vrf-target target:65000:20            interface "ABC" create                address 20.20.20.1/24                sap 1/1/1 create                exit            exit

Service VPRN verification

A:R3# show service id 20 base =============================================================================== Service Basic Information =============================================================================== Service Id        : 20                  Vpn Id            : 0 Service Type      : VPRN Name              : (Not Specified) Description       : (Not Specified) Customer Id       : 100                 Creation Origin   : manual Last Status Change: 11/16/2015 10:00:16 Last Mgmt Change  : 11/16/2015 10:00:16 Admin State       : Up                  Oper State        : Up Route Dist.       : 65000:100           VPRN Type         : regular AS Number         : None                Router Id         : 50.50.50.3 ECMP              : Enabled             ECMP Max Routes   : 1 Max IPv4 Routes   : No Limit            Auto Bind         : LDP Max IPv6 Routes   : No Limit Ignore NH Metric  : Disabled Hash Label        : Disabled Vrf Target        : target:65000:20 Vrf Import        : None Vrf Export        : None MVPN Vrf Target   : None MVPN Vrf Import   : None MVPN Vrf Export   : None Car. Sup C-VPN    : Disabled Label mode        : vrf BGP VPN Backup    : Disabled BGP Export Inacti*: Disabled SAP Count         : 1                   SDP Bind Count    : 0 ------------------------------------------------------------------------------- Service Access & Destination Points ------------------------------------------------------------------------------- Identifier                               Type         AdmMTU  OprMTU  Adm  Opr ------------------------------------------------------------------------------- sap:1/1/1                                null         1514    1514    Up   Up =============================================================================== * indicates that the corresponding row element may have been truncated.

Step 4: PE-CE routing

OSPF have to be configure under service vprn 20 branch in the PE routers, NOT user global routing.

OSPF basic configuration

PE routers (R1 and R3)	CE routers (R4 and R5)
configure service vprn 20                  ospf                         area 0.0.0.0                    interface "ABC"                        no shutdown                    exit                exit            exit	router ospf 1 network 0.0.0.0 255.255.255.255 area 0

VPN-IPv4 routes received from the MP-BGP in PE routers has to be exported in the OSPF using policy

OSPF export configuration

PE routers (R1 and R3)

configure router policy-options          begin          policy-statement "abcRT"                entry 10                    from                        protocol bgp-vpn                    exit                    action accept                    exit                exit            exit           commit           exit configure service vprn 20 ospf export "abcRT"

PE-CE OSPF Verification

A:R3# show router 20 ospf neighbor =============================================================================== OSPFv2 (0) all neighbors =============================================================================== Interface-Name                   Rtr Id          State      Pri  RetxQ   TTL   Area-Id ------------------------------------------------------------------------------- ABC                              5.5.5.5         Full       1    0       39   0.0.0.0 ------------------------------------------------------------------------------- No. of Neighbors: 1 =============================================================================== R5# sh ip route ospf …output omitted… Gateway of last resort is not set      4.0.0.0/32 is subnetted, 1 subnets O E2     4.4.4.4 [110/101] via 20.20.20.1, 00:09:39, Ethernet0/0      10.0.0.0/24 is subnetted, 1 subnets O E2     10.10.10.0 [110/1] via 20.20.20.1, 00:09:39, Ethernet0/0

*The exercise is done in a virtual environment using Unetlab. Output may vary in real devices. Ask me if you need the lab files.