Wednesday, 28 December 2016

MPLS CHAPTER 10

MPLS CHAPTER 10
 QUESTIONS:
 33. Why is redistribution needed in MPLS L3VPN ?
 34. When is a RD, RT and VPN label added to a route ?
 35. In BGP configuration are you causing an Import or Export ?

 Solution :
 33. Why is redistribution needed in MPLS L3VPN ?
 --> For the Communication of VRF aware routes of PE to global routes of
      CE we are doing redistribution.
 

34. When is a RD, RT and VPN label added to a route ?

CE Advertised route -> ipv4 route sent from CE to PE ->Recieved on VRF->
-> Exported to BGP as VPNv4 route with RD/RT -> send PE to PE ->
Imported into VRF based on RT -> IPv4 Route sent from PE to CE -> CE learnd route

--> when routes Reaches from CE to PE , PE export routes to MPBGP with
Local RD , RT(export) and send to other PE router.

35. In BGP configuration are you causing an Import or Export ?

--> It depends upon which MPLS topology we are using :

VPNv4 routes can have more than one route target
  . allows for complex VPN topologies
  full mesh
  import and export same everywhere
  hub and spoke
  spokes import only hubs routes
  Central services
  Multiple VPNs can import from a central site or from a central serv
  Managment VPNs
  Management Loopback on CE routers can be exported into special
  management VPN.
 
 Let us do it with our example:

 diag :



PE0R1 CONFIG :

PE0R1#sh run | se ospf
router ospf 101 vrf Cust_site1
 log-adjacency-changes
 redistribute bgp 100 metric 555 subnets
 network 10.1.14.0 0.0.0.255 area 0
router ospf 1
 log-adjacency-changes
 network 0.0.0.0 255.255.255.255 area 0
  redistribute ospf 101 vrf Cust_site1
PE0R1#sh run | se eigrp
router eigrp 1
 auto-summary
 !
 address-family ipv4 vrf Cust_site2
  redistribute bgp 100 metric 1 1 1 1 1
  network 10.0.0.0
  no auto-summary
  autonomous-system 15
 exit-address-family
router eigrp 15
 auto-summary
  redistribute eigrp 15
PE0R1#sh run | se bgp
  redistribute bgp 100 metric 1 1 1 1 1
 redistribute bgp 100 metric 555 subnets
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 neighbor 3.3.3.3 remote-as 100
 neighbor 3.3.3.3 update-source Loopback1
 no auto-summary
 !
 address-family vpnv4
  neighbor 3.3.3.3 activate
  neighbor 3.3.3.3 send-community extended
 exit-address-family
 !
 address-family ipv4 vrf Cust_site2
  redistribute eigrp 15
  no synchronization
 exit-address-family
 !
 address-family ipv4 vrf Cust_site1
  redistribute ospf 101 vrf Cust_site1
  no synchronization
 exit-address-family

 PE0R1#sh bgp vpnv4 unicast vrf Cust_site1
BGP table version is 17, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 1.1.1.1:1 (default for vrf Cust_site1)
*> 4.4.4.1/32       10.1.14.4               11         32768 ?
*>i6.6.6.1/32       3.3.3.3                  1    100      0 ?
*> 10.1.14.0/24     0.0.0.0                  0         32768 ?
*>i10.1.36.0/24     3.3.3.3                  0    100      0 ?
PE0R1#sh bgp vpnv4 unicast vrf Cust_site1 4.4.4.1/32
BGP routing table entry for 1.1.1.1:1:4.4.4.1/32, version 8
Paths: (1 available, best #1, table Cust_site1)
  Advertised to update-groups:
     1
  Local
    10.1.14.4 from 0.0.0.0 (1.1.1.1)
      Origin incomplete, metric 11, localpref 100, weight 32768, valid, sourced, best
      Extended Community: OSPF DOMAIN ID:0x0005:0x000000650200 RT:1.1.1.1:101
        OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:10.1.14.1:0
      mpls labels in/out 503/nolabel
PE0R1#sh bgp vpnv4 unicast vrf Cust_site1 6.6.6.1/32
BGP routing table entry for 1.1.1.1:1:6.6.6.1/32, version 16
Paths: (1 available, best #1, table Cust_site1)
  Not advertised to any peer
  Local, imported path from 3.3.3.3:1:6.6.6.1/32
    3.3.3.3 (metric 21) from 3.3.3.3 (3.3.3.3)
      Origin incomplete, metric 1, localpref 100, valid, internal, best
      Extended Community: RT:3.3.3.3:101
      mpls labels in/out nolabel/21

FOR ROUTER PE0R3:

PE0R3#sh run | se rip
router rip
 version 2
 !
 address-family ipv4 vrf Cust_site1
  redistribute bgp 100 metric 3
  network 10.0.0.0
  no auto-summary
 exit-address-family
  redistribute rip
PE0R3#sh run | se bgp
  redistribute bgp 100 metric 3
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 100
 neighbor 1.1.1.1 update-source Loopback1
 no auto-summary
 !
 address-family vpnv4
  neighbor 1.1.1.1 activate
  neighbor 1.1.1.1 send-community extended
  neighbor 1.1.1.1 next-hop-self
 exit-address-family
 !
 address-family ipv4 vrf Cust_site2
  neighbor 10.1.37.7 remote-as 200
  neighbor 10.1.37.7 activate
  no synchronization
 exit-address-family
 !
 address-family ipv4 vrf Cust_site1
  redistribute rip
  no synchronization
 exit-address-family

PE0R3#sh bgp vpnv4 unicast vrf Cust_site1
BGP table version is 16, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 3.3.3.3:1 (default for vrf Cust_site1)
*>i4.4.4.1/32       1.1.1.1                 11    100      0 ?
*> 6.6.6.1/32       10.1.36.6                1         32768 ?
*>i10.1.14.0/24     1.1.1.1                  0    100      0 ?
*> 10.1.36.0/24     0.0.0.0                  0         32768 ?
PE0R3#sh bgp vpnv4 unicast vrf Cust_site2
BGP table version is 16, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: 3.3.3.3:2 (default for vrf Cust_site2)
*>i5.5.5.1/32       1.1.1.1            2297856    100      0 ?
*> 7.7.7.1/32       10.1.37.7                0             0 200 ?
*>i10.1.15.0/24     1.1.1.1                  0    100      0 ?
r> 10.1.37.0/24     10.1.37.7                0             0 200 ?
PE0R3#sh bgp vpnv4 unicast vrf Cust_site2 5.5.5.1/32
BGP routing table entry for 3.3.3.3:2:5.5.5.1/32, version 11
Paths: (1 available, best #1, table Cust_site2)
  Advertised to update-groups:
     1
  Local, imported path from 1.1.1.1:2:5.5.5.1/32
    1.1.1.1 (metric 21) from 1.1.1.1 (1.1.1.1)
      Origin incomplete, metric 2297856, localpref 100, valid, internal, best
      Extended Community: RT:1.1.1.1:102
        Cost:pre-bestpath:128:2297856 (default-2145185791) 0x8800:32768:0
        0x8801:15:640000 0x8802:65281:1657856 0x8803:65281:1500
      mpls labels in/out nolabel/505
PE0R3#sh bgp vpnv4 unicast vrf Cust_site2 7.7.7.1/32
BGP routing table entry for 3.3.3.3:2:7.7.7.1/32, version 2
Paths: (1 available, best #1, table Cust_site2)
  Advertised to update-groups:
     2
  200
    10.1.37.7 from 10.1.37.7 (7.7.7.1)
      Origin incomplete, metric 0, localpref 100, valid, external, best
      Extended Community: RT:3.3.3.3:102
      mpls labels in/out 19/nolabel

 

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