Dynamic Tunnels - MPLS RSVP TE based
Configuration management is a one of the trickier part when it comes to scale environment. Its becomes even more cumbersome to manage when it has a requirement of establishing the full mesh. Today I am going to talk about such one topic, its MPLS LSP configuration.
If you are using the MPLS LSP in your core, it requires to be of full mesh or single hop based on you network design. You may end up configuring many lines of configuration based on how many routers are there in that full mesh topology.
There is a simple configuration option available in JUNOS to signal LSPs to all the peers you are interested in just few configuration lines, its dynamic-tunnel configuration under routing-option hierarchy.
In IP address management, there is a separate subnet or pool kept on side to allocate the loopback address on the routers. You can use that whole pool and instruct the ingress router to signal the P2P LSPs to all other PEs or peers.
To explain it further, I am using the same topology used in Overload bit blog post.
In above topology, R2 is my DUT and I want to signal the LSP to R6 and R5 using dynamic-tunnel configuration.
To configure the RSVP TE based dynamic-tunnel, you can use the customized template or default template. I will use and define the customized template under protocol mpls stanza with just basic configuration as shown below which I will reference in my RSVP-TE based dynamic-tunnel configuration. I
root@r2# show protocols mpls
traffic-engineering {
mpls-forwarding;
}
label-switched-path my-dynamic-lsp-template {
template;
adaptive;
}
label-switched-path my-dynamic-lsp-template1 {
template;
adaptive;
}
Now let’s use above template in dynamic-tunnel configuration and define the subnet or specific IP or group of IPs under specific dynamic-tunnel name to signal the actual LSPs.
root@r2# show routing-options dynamic-tunnels
my-dynamic-tunnel {
rsvp-te my-dynamic-rsvp-te {
label-switched-path-template {
my-dynamic-lsp-template;
}
destination-networks {
192.168.1.6/32;
}
}
}
As you can see in following template, I have configured the R5 and R6 loopback address under same dynamic-tunnel stanza so RSVP module use the LSP parameters from the template my-dynamic-lsp-template and destination or to address from the destination-networks stanza.
my-dynamic-tunnel1 {
rsvp-te my-dynamic-rsvp-te1 {
label-switched-path-template {
my-dynamic-lsp-template;
}
destination-networks {
192.168.1.6/32;
192.168.1.5/32;
}
}
}
Let’s verify if LSPs are being signaled and they are up and running, lets pick the name of one of the LSP signaled 192.168.1.5:dt-rsvp-my-dynamic-tunnel1 and it is matching the dynamic tunnel name configured my-dynamic-tunnel1 with dt-rsvp- prepended to identify the tunnels are dynamic-tunnel and signaling protocol is RSVP:
root@r2# run show mpls lsp ingress
Ingress LSP: 3 sessions
To From State Rt P ActivePath LSPname
192.168.1.5 192.168.1.2 Up 0 * 192.168.1.5:dt-rsvp-my-dynamic-tunnel1
192.168.1.6 192.168.1.2 Up 0 * 192.168.1.6:dt-rsvp-my-dynamic-tunnel
192.168.1.6 192.168.1.2 Up 0 * 192.168.1.6:dt-rsvp-my-dynamic-tunnel1
Total 3 displayed, Up 3, Down 0
[edit]
root@r2# run show rsvp session ingress
Ingress RSVP: 3 sessions
To From State Rt Style Labelin Labelout LSPname
192.168.1.5 192.168.1.2 Up 0 1 SE - 16869 192.168.1.5:dt-rsvp-my-dynamic-tunnel1
192.168.1.6 192.168.1.2 Up 0 1 SE - 16867 192.168.1.6:dt-rsvp-my-dynamic-tunnel
192.168.1.6 192.168.1.2 Up 0 1 SE - 16868 192.168.1.6:dt-rsvp-my-dynamic-tunnel1
Total 3 displayed, Up 3, Down 0
In above example, I configured 192.168.1.6 two times to cover the RSVP LSP ECMP scenario, R2 has signaled two dynamic LSPs to R6, one using my-dynamic-tunnel and another using my-dynamic-tunnel1 dynamic-tunnel configuration.
As you can see the R6’s loopback is reachable via two dynamic LSP for ECMP load balancing.
root@r2# run show route 192.168.1.6
inet.0: 30 destinations, 36 routes (30 active, 0 holddown, 0 hidden)
@ = Routing Use Only, # = Forwarding Use Only
+ = Active Route, - = Last Active, * = Both
192.168.1.6/32 @[IS-IS/18] 00:03:23, metric 30
> to 1.1.23.2 via ge-0/0/1.23
#[RSVP/7/3] 00:03:23, metric 30
to 1.1.23.2 via ge-0/0/1.23, label-switched-path 192.168.1.6:dt-rsvp-my-dynamic-tunnel
> to 1.1.23.2 via ge-0/0/1.23, label-switched-path 192.168.1.6:dt-rsvp-my-dynamic-tunnel1
[LDP/9] 00:03:23, metric 1
> to 1.1.23.2 via ge-0/0/1.23, Push 16866
inet.3: 4 destinations, 6 routes (4 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
192.168.1.6/32 *[RSVP/7/3] 00:03:23, metric 30
to 1.1.23.2 via ge-0/0/1.23, label-switched-path 192.168.1.6:dt-rsvp-my-dynamic-tunnel
> to 1.1.23.2 via ge-0/0/1.23, label-switched-path 192.168.1.6:dt-rsvp-my-dynamic-tunnel1
[LDP/9] 00:03:23, metric 1
> to 1.1.23.2 via ge-0/0/1.23, Push 16866
[Tunnel/305] 10:32:11
Tunnel
Forwarding path is also configured with the multiple ECMP paths to reach R6 from R2:
root@r2# run show route forwarding-table destination 192.168.1.6 table default
Routing table: default.inet
Internet:
Enabled protocols: Bridging,
Destination Type RtRef Next hop Type Index NhRef Netif
192.168.1.6/32 user 0 ulst 1048578 2
1.1.23.2 Push 16867 637 2 ge-0/0/1.23
1.1.23.2 Push 16868 638 2 ge-0/0/1.23
[edit]
root@r2# run show route forwarding-table destination 192.168.1.6 table default extensive
Routing table: default.inet [Index 0]
Internet:
Enabled protocols: Bridging,
Destination: 192.168.1.6/32
Route type: user
Route reference: 0 Route interface-index: 0
Multicast RPF nh index: 0
P2mpidx: 0
Flags: sent to PFE, rt nh decoupled
Next-hop type: unilist Index: 1048578 Reference: 2
Nexthop: 1.1.23.2
Next-hop type: Push 16867 Index: 637 Reference: 2
Load Balance Label: None
Next-hop interface: ge-0/0/1.23 Weight: 0x1
Nexthop: 1.1.23.2
Next-hop type: Push 16868 Index: 638 Reference: 2
Load Balance Label: None
Next-hop interface: ge-0/0/1.23 Weight: 0x1
For reference, I have captured the rsvp session and mpls LSP extensive outputs:
RSVP session extensive output
[edit]
root@r2# run show rsvp session ingress extensive
Ingress RSVP: 2 sessions
192.168.1.6
From: 192.168.1.2, LSPstate: Up, ActiveRoute: 0
LSPname: 192.168.1.6:dt-rsvp-my-dynamic-tunnel, LSPpath: Primary
LSPtype: Dynamic Configured <<<<< indicates dynamically configured
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: 16867
Resv style: 1 SE, Label in: -, Label out: 16867
Time left: -, Since: Thu May 7 21:08:28 2020
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 2 receiver 37876 protocol 0
Enhanced FRR: Enabled (Downstream)
PATH rcvfrom: localclient
Adspec: sent MTU 1500
Path MTU: received 1500
PATH sentto: 1.1.23.2 (ge-0/0/1.23) 2 pkts
outgoing message state: refreshing, Message ID: 22531, Epoch: 4961110
RESV rcvfrom: 1.1.23.2 (ge-0/0/1.23) 2 pkts, Entropy label: Yes
incoming message handle: R-23832/2, Message ID: 56575, Epoch: 7352319
Explct route: 1.1.23.2 1.1.35.2 1.1.56.2
Record route: <self> 1.1.23.2 1.1.35.2 1.1.56.2
192.168.1.6
From: 192.168.1.2, LSPstate: Up, ActiveRoute: 0
LSPname: 192.168.1.6:dt-rsvp-my-dynamic-tunnel1, LSPpath: Primary
LSPtype: Dynamic Configured <<<<< indicates dynamically configured
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: 16868
Resv style: 1 SE, Label in: -, Label out: 16868
Time left: -, Since: Thu May 7 21:09:52 2020
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 1 receiver 37877 protocol 0
Enhanced FRR: Enabled (Downstream)
PATH rcvfrom: localclient
Adspec: sent MTU 1500
Path MTU: received 1500
PATH sentto: 1.1.23.2 (ge-0/0/1.23) 2 pkts
outgoing message state: refreshing, Message ID: 22532, Epoch: 4961110
RESV rcvfrom: 1.1.23.2 (ge-0/0/1.23) 2 pkts, Entropy label: Yes
incoming message handle: R-23833/2, Message ID: 56576, Epoch: 7352319
Explct route: 1.1.23.2 1.1.35.2 1.1.56.2
Record route: <self> 1.1.23.2 1.1.35.2 1.1.56.2
Total 2 displayed, Up 2, Down 0
MPLS LSP extensive output
root@r2# run show mpls lsp ingress extensive
Ingress LSP: 2 sessions
192.168.1.6
From: 192.168.1.2, State: Up, ActiveRoute: 0, LSPname: 192.168.1.6:dt-rsvp-my-dynamic-tunnel
ActivePath: (primary)
LSPtype: Dynamic Configured, Penultimate hop popping <<<<< indicates dynamically configured
LoadBalance: Random
Follow destination IGP metric
Encoding type: Packet, Switching type: Packet, GPID: IPv4
LSP Self-ping Status : Enabled
*Primary State: Up
Priorities: 7 0
SmartOptimizeTimer: 180
Flap Count: 0
MBB Count: 0
Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 30)
1.1.23.2 S 1.1.35.2 S 1.1.56.2 S
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
1.1.23.2(Label=16867) 1.1.35.2(Label=31263) 1.1.56.2(Label=3)
15 May 8 07:26:50.508 CSPF: computation result accepted 1.1.23.2 1.1.35.2 1.1.56.2
14 May 7 21:08:29.670 Self-ping ended successfully
13 May 7 21:08:29.224 Selected as active path
12 May 7 21:08:29.222 Up
11 May 7 21:08:29.222 Self-ping started
10 May 7 21:08:29.222 Self-ping enqueued
9 May 7 21:08:29.222 Record Route: 1.1.23.2(Label=16867) 1.1.35.2(Label=31263) 1.1.56.2(Label=3)
8 May 7 21:08:28.927 Originate Call
7 May 7 21:08:28.927 CSPF: computation result accepted 1.1.23.2 1.1.35.2 1.1.56.2
6 May 7 21:08:00.196 CSPF failed: no route toward 192.168.1.6[2 times]
5 May 7 21:07:33.306 Clear Call: CSPF computation failed
4 May 7 21:07:33.306 CSPF: link down/deleted: 0.0.0.0(0.0.0.0:0)(r5.02/0.0.0.0)->0.0.0.0(192.168.1.6:0)(r6.00/192.168.1.6)
3 May 7 21:07:31.765 1.1.56.2: RSVP System error, subcode 4: protocol shutdown[4 times]
2 May 7 21:07:30.883 Originate Call
1 May 7 21:07:30.883 CSPF: computation result accepted 1.1.23.2 1.1.35.2 1.1.56.2
Created: Thu May 7 21:07:30 2020
192.168.1.6
From: 192.168.1.2, State: Up, ActiveRoute: 0, LSPname: 192.168.1.6:dt-rsvp-my-dynamic-tunnel1
ActivePath: (primary)
LSPtype: Dynamic Configured, Penultimate hop popping <<<<< indicates dynamically configured
LoadBalance: Random
Follow destination IGP metric
Encoding type: Packet, Switching type: Packet, GPID: IPv4
LSP Self-ping Status : Enabled
*Primary State: Up
Priorities: 7 0
SmartOptimizeTimer: 180
Flap Count: 0
MBB Count: 0
Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 30)
1.1.23.2 S 1.1.35.2 S 1.1.56.2 S
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID):
1.1.23.2(Label=16868) 1.1.35.2(Label=31264) 1.1.56.2(Label=3)
9 May 8 07:26:50.511 CSPF: computation result accepted 1.1.23.2 1.1.35.2 1.1.56.2
8 May 7 21:09:52.729 Self-ping ended successfully
7 May 7 21:09:52.398 Selected as active path
6 May 7 21:09:52.397 Up
5 May 7 21:09:52.397 Self-ping started
4 May 7 21:09:52.397 Self-ping enqueued
3 May 7 21:09:52.397 Record Route: 1.1.23.2(Label=16868) 1.1.35.2(Label=31264) 1.1.56.2(Label=3)
2 May 7 21:09:52.034 Originate Call
1 May 7 21:09:52.034 CSPF: computation result accepted 1.1.23.2 1.1.35.2 1.1.56.2
Created: Thu May 7 21:09:52 2020
Total 2 displayed, Up 2, Down 0