IOS XE 15.5
IOS XR 5.3
The topology for this demo:
We haven't discussed this yet in this section but just as important to our previous post is the label ranges each LSR will allocate to local labels. Currently, IOS and IOS XR routers are allocating the same starting points, 16 for IOS and 24000 for IOS XR. I am going to disable MPLS on all the routers, and configure a label range for each router. R1-R6 is going to be 100-199, 200-299 etc. IOS XR will follow suit, XR1-XR6 is going to be 24100-24199, 24200-24299 etc. I can't see us neededing more than 100 labels per LSR.
At the same time we do this we can also allocate static label ranges for IOS. This will be needed a bit later when we need to allocate a label range for static configuration of labels. R1-R6 will use 1100-1199, 2200-2299 etc. This is to make it obvious which router is doing what.
Since we already have MPLS running everywhere, we'll have to disable it.
IOS
router ospf 1
no mpls ldp autoconfig
XR
router ospf 1
area 0
no mpls ldp auto-config
exit
exit
!
no mpls ldp
commit
OK, now that MPLS has been disabled, we'll go ahead and set the ranges we need. I'll configure them here the way they need to be setup and then copy them into the CLI.
R1
mpls label range 100 199 static 1100 1199
R2
mpls label range 200 299 static 2200 2299
R3
mpls label range 300 399 static 3300 3399
R4
mpls label range 400 499 static 4400 4499
R5
mpls label range 500 599 static 5500 5599
R6
mpls label range 600 699 static 6600 6699
XR1
mpls label range table 0 24100 24199
XR2
mpls label range table 0 24200 24299
XR3
mpls label range table 0 24300 24399
XR4
mpls label range table 0 24400 24499
XR5
mpls label range table 0 24500 24599
XR6
mpls label range table 0 24600 24699
Now the fun begins!
Let's enable MPLS everywhere with autoconfig.
IOS
router ospf 1
mpls ldp autoconfig
XR
router ospf 1
area 0
mpls ldp auto
exit
exit
mpls ldp
commit
I want to keep the LIB as small as possible, so we are going to enable global host routes for IOS and XR.
IOS
mpls ldp label
allocate global host-routes
XR
mpls ldp
address-family ipv4
label
local
allocate for host-routes
commit
Now we can quick verfiy on R1 our LFIB.
R1#sh mpls forwarding-table
*Nov 20 23:11:28.726: %SYS-5-CONFIG_I: Configured from console by console
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
114 24204 192.168.1.2/32 0 Gi1.112 10.1.12.12
24502 192.168.1.2/32 0 Gi1.115 10.1.15.15
115 24122 192.168.1.3/32 0 Gi1.111 10.1.11.11
24515 192.168.1.3/32 0 Gi1.115 10.1.15.15
116 24516 192.168.1.4/32 0 Gi1.115 10.1.15.15
117 24208 192.168.1.5/32 0 Gi1.112 10.1.12.12
24517 192.168.1.5/32 0 Gi1.115 10.1.15.15
118 24205 192.168.1.6/32 0 Gi1.112 10.1.12.12
24518 192.168.1.6/32 0 Gi1.115 10.1.15.15
119 Pop Label 192.168.1.11/32 0 Gi1.111 10.1.11.11
120 Pop Label 192.168.1.12/32 0 Gi1.112 10.1.12.12
121 24201 192.168.1.13/32 0 Gi1.112 10.1.12.12
122 24100 192.168.1.14/32 0 Gi1.111 10.1.11.11
24501 192.168.1.14/32 0 Gi1.115 10.1.15.15
123 Pop Label 192.168.1.15/32 1121 Gi1.115 10.1.15.15
124 24203 192.168.1.16/32 0 Gi1.112 10.1.12.12
24503 192.168.1.16/32 0 Gi1.115 10.1.15.15
Awesome, all /32 prefixes are in there.
Now we get to the meat and taters of this setup, we've already hit the label range options. Specifically, if you look at the the output for 192.168.1.16/32, you'll see the label values already showing specifics. 24203 connects is from XR2 and 24503 is from XR5. So we know who are directly connected next hops are.
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