Juniper MPLS.0 Table

MPLS.0 Table:

The mpls.0 table in JUNOS is an MPLS label Switching Table. It tell the router what to do when a packet is received with a certain label. It is almost like a MAC address table in Layer-2 switches. This routing table is used on transit routers to route packets to the next router along an LSP.

In JUNOS the values of these labels are assigned as follows:

Label Value Use
0 through 15 Reserved by IETF
16 through 1023 Reserved for static LSP assignment
1024 through 9999 Reserved for internal use (for example, CCC labels, L3VPN Inner labels)
10,000 through 99,999 Reserved for static LSP assignment
100,000 through 1,048,575 Reserved for dynamic label assignment

MPLS.0 table can be viewed using:

Label Value	Use
0 through 15	Reserved by IETF
16 through 1023	Reserved for static LSP assignment
1024 through 9999	Reserved for internal use (for example, CCC labels, L3VPN Inner labels)
10,000 through 99,999	Reserved for static LSP assignment
100,000 through 1,048,575	Reserved for dynamic label assignment

user@Router > show route table mpls.0
On any of the transit router, execute show route table mpls.0 to view what action will be performed on the MPLS packets with this label. The action could be Pop the label, Swap the label with another label etc. In case of Penultimate Hop Router, two label entries will be shown: one with Stack bit equal to zero, S=0, and the other with S=1 (this is implicit). This last label will be removed and IPv4 packet will be sent to the next hop, Egress, router.

Following added 2010 using JUNOS version 10.0 Textual Description of network. r1 connects to r3 and r2 r2 connects to r1, r3 and r4 r3 connects to r1, r2, r4 and r5 r4 connects to r2, r3 and r5. r5 connects to r3, r4, r6, r7 r6 connects to r5 and r7 and r7 [twice] r7 connects to r5 and r6 and r6. r3 is ABR for area 10 and 0. r4 is ABR for area 10 and 0. r5 is ABR for area 0 and area 1 r6 and r7 are routers in area 1. This RSVP LSP starts from r1 and ends at r7. Hence r1 is ingress router, r7 is egress. In between, it goes through r3 which is 10.0.4.13, r5 router which is PHP [Penultimate Hop Popper] and has IP address 10.0.2.1, then egress router r7 10.0.8.10. To signal LSP using RSVP following config is used: label-switched-path r1-to-r7 { to 10.0.8.10; no-cspf; } CSPF is turned off becuase there are multiple OSPF areas between R1 and R7. TED is confined to an OSPF area. So we can use cspf in RSVP triggered LSPs that traverse only a single area where TED [Traffic Engineering Database] on each router has information about every other router in that area and has entries for all the router interface addresses/networks within that area. For an RSVP triggered LSP that traverses multiple OSPF areas, cspf has to be turned off and hence all TE capabilities of RSVP are lost. RSVP becomes almost like LDP, following IGP. The above configured LSP can be seen as follows: juniper@m10i> show mpls lsp logical-system r1 ingress name r1-to-r7 Ingress LSP: 3 sessions To From State Rt P ActivePath LSPname 10.0.8.10 10.0.6.1 Up 0 * r1-to-r7 Total 1 displayed, Up 1, Down 0 juniper@m10i> show mpls lsp logical-system r1 ingress name r1-to-r7 extensive Ingress LSP: 3 sessions 10.0.8.10 From: 10.0.6.1, State: Up, ActiveRoute: 0, LSPname: r1-to-r7 ActivePath: (primary) LoadBalance: Random Encoding type: Packet, Switching type: Packet, GPID: IPv4 *Primary State: Up Priorities: 7 0 SmartOptimizeTimer: 180 Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt 20=Node-ID): 10.0.4.13 10.0.2.1 10.0.8.10 5 Jun 4 16:13:38.600 Selected as active path 4 Jun 4 16:13:38.597 Record Route: 10.0.4.13 10.0.2.1 10.0.8.10 3 Jun 4 16:13:38.597 Up 2 Jun 4 16:12:53.588 10.0.8.10: MPLS label allocation failure[6 times] 1 Jun 4 16:10:29.545 Originate Call Created: Fri Jun 4 16:10:29 2010 Total 1 displayed, Up 1, Down 0 Since this is the ingress [not a transit] router for LSP r1-to-r7, we have following mpls.0 table: juniper@m10i> show route table mpls.0 logical-system r1 mpls.0: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 05:27:52, metric 1 Receive 1 *[MPLS/0] 05:27:52, metric 1 Receive 2 *[MPLS/0] 05:27:52, metric 1 Receive The ingress router puts a label on native IP packet. The label can be gleaned from following command: juniper@m10i> show route table inet.3 logical-system r1 extensive 10.0.8.10 inet.3: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden) 10.0.8.10/32 (1 entry, 0 announced) State: <FlashAll> *RSVP Preference: 7 Next hop type: Router Next-hop reference count: 3 Next hop: 10.0.4.13 via fe-0/1/0.0 weight 0x1, selected Label-switched-path r1-to-r7 Label operation: Push 299840 State: <Active Int> Age: 1:43:06 Metric: 10 Task: RSVP AS path: I Note that inet.3 table, which stores all RSVP/LDP LSP on ingress router, is only populated on INGRESS LSP router. BGP can use this table to resolve next hops for learned routes. If BGP has a route with the next hop of 10.0.8.10 on r1, that traffic would take the above LSP. Lets go to next router r3. R3 is a transit router for this LSP. juniper@m10i> show mpls lsp logical-system r3 name r1-to-r7 transit Transit LSP: 2 sessions To From State Rt Style Labelin Labelout LSPname 10.0.8.10 10.0.6.1 Up 1 1 FF 299840 299776 r1-to-r7 Total 1 displayed, Up 1, Down 0 So R3 gets the label 299840 and swaps it with 299776. Extensive version of the above command is: juniper@m10i> show mpls lsp logical-system r3 name r1-to-r7 transit extensive Transit LSP: 2 sessions 10.0.8.10 From: 10.0.6.1, LSPstate: Up, ActiveRoute: 1 LSPname: r1-to-r7, LSPpath: Primary Suggested label received: -, Suggested label sent: - Recovery label received: -, Recovery label sent: 299776 Resv style: 1 FF, Label in: 299840, Label out: 299776 Time left: 150, Since: Fri Jun 4 16:10:29 2010 Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500 Port number: sender 1 receiver 9937 protocol 0 PATH rcvfrom: 10.0.4.14 (fe-0/1/1.0) 151 pkts Adspec: received MTU 1500 sent MTU 1500 PATH sentto: 10.0.2.1 (ge-0/3/2.0) 152 pkts RESV rcvfrom: 10.0.2.1 (ge-0/3/2.0) 145 pkts Record route: 10.0.4.14 <self> 10.0.2.1 10.0.8.10 Total 1 displayed, Up 1, Down 0 juniper@m10i> show route table mpls.0 logical-system r3 mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 02:50:35, metric 1 Receive 1 *[MPLS/0] 02:50:35, metric 1 Receive 2 *[MPLS/0] 02:50:35, metric 1 Receive 299824 *[RSVP/7] 02:01:02, metric 1 > to 10.0.2.1 via ge-0/3/2.0, label-switched-path r1-to-r5 299824(S=0) *[RSVP/7] 02:01:02, metric 1 > to 10.0.2.1 via ge-0/3/2.0, label-switched-path r1-to-r5 299840 *[RSVP/7] 01:47:51, metric 1 > to 10.0.2.1 via ge-0/3/2.0, label-switched-path r1-to-r7 we can ignore label 299824, since it belongs to another LSP for which r3 is a penultimate hop router since S=0. Extensive version for only our concerned label 299840 is: juniper@m10i> show route table mpls.0 logical-system r3 label 299840 extensive mpls.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden) 299840 (1 entry, 1 announced) TSI: KRT in-kernel 299840 /52 -> {Swap 299776} *RSVP Preference: 7 Next hop type: Router, Next hop index: 1115 Next-hop reference count: 3 Next hop: 10.0.2.1 via ge-0/3/2.0 weight 0x1, selected Label-switched-path r1-to-r7 Label operation: Swap 299776 State: <Active Int AckRequest> Age: 1:49:35 Metric: 1 Task: RSVP Announcement bits (1): 1-KRT AS path: I Next we go to r5 router. juniper@m10i> show mpls lsp logical-system r5 name r1-to-r7 Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 1 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 1 sessions To From State Rt Style Labelin Labelout LSPname 10.0.8.10 10.0.6.1 Up 1 1 FF 299776 3 r1-to-r7 Total 1 displayed, Up 1, Down 0 Here outgoing label is 3 which means R5 is a PHP. This is confirmed from mpls.0 table: juniper@m10i> show route table mpls.0 logical-system r5 mpls.0: 5 destinations, 5 routes (5 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 02:58:06, metric 1 Receive 1 *[MPLS/0] 02:58:06, metric 1 Receive 2 *[MPLS/0] 02:58:06, metric 1 Receive 299776 *[RSVP/7] 01:56:22, metric 1 > to 10.0.8.10 via fe-1/2/0.0, label-switched-path r1-to-r7 299776(S=0) *[RSVP/7] 01:56:22, metric 1 > to 10.0.8.10 via fe-1/2/0.0, label-switched-path r1-to-r7 Note that label 3 doesn't appear at all in the table. Because 3 is never put on the packet as a label. 3 only tells this r5 router to do PHP i.e take the label out and send the rest of the packet as is. In our case since S=0 so we are taking the last label out making the stack = 0. Extended version of above for just our label 299776 is: juniper@m10i> show route table mpls.0 logical-system r5 label 299776 extensive mpls.0: 5 destinations, 5 routes (5 active, 0 holddown, 0 hidden) 299776 (1 entry, 1 announced) TSI: KRT in-kernel 299776 /52 -> {Pop } *RSVP Preference: 7 Next hop type: Router, Next hop index: 1113 Next-hop reference count: 3 Next hop: 10.0.8.10 via fe-1/2/0.0 weight 0x1, selected Label-switched-path r1-to-r7 Label operation: Pop State: <Active Int AckRequest> Age: 1:56:53 Metric: 1 Task: RSVP Announcement bits (1): 1-KRT AS path: I 299776(S=0) (1 entry, 1 announced) TSI: KRT in-kernel 299776 /56 -> {Pop } *RSVP Preference: 7 Next hop type: Router, Next hop index: 1114 Next-hop reference count: 2 Next hop: 10.0.8.10 via fe-1/2/0.0 weight 0x1, selected Label-switched-path r1-to-r7 Label operation: Pop State: <Active Int AckRequest> Age: 1:56:53 Metric: 1 Task: RSVP Announcement bits (1): 1-KRT AS path: I Lets go on to r7. juniper@m10i> show mpls lsp logical-system r7 Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 1 sessions To From State Rt Style Labelin Labelout LSPname 10.0.8.10 10.0.6.1 Up 0 1 FF 3 - r1-to-r7 Total 1 displayed, Up 1, Down 0 Transit LSP: 0 sessions Total 0 displayed, Up 0, Down 0 juniper@m10i> show mpls lsp logical-system r7 extensive name r1-to-r7 Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 1 sessions 10.0.8.10 From: 10.0.6.1, LSPstate: Up, ActiveRoute: 0 LSPname: r1-to-r7, LSPpath: Primary Suggested label received: -, Suggested label sent: - Recovery label received: -, Recovery label sent: - Resv style: 1 FF, Label in: 3, Label out: - Time left: 155, Since: Fri Jun 4 16:13:38 2010 Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500 Port number: sender 1 receiver 9937 protocol 0 PATH rcvfrom: 10.0.8.9 (fe-1/2/1.0) 165 pkts Adspec: received MTU 1500 PATH sentto: localclient RESV rcvfrom: localclient Record route: 10.0.4.14 10.0.2.2 10.0.8.9 <self> Total 1 displayed, Up 1, Down 0 Transit LSP: 0 sessions Total 0 displayed, Up 0, Down 0 juniper@m10i> show route table mpls.0 logical-system r7 mpls.0: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 0 *[MPLS/0] 02:02:34, metric 1 Receive 1 *[MPLS/0] 02:02:34, metric 1 Receive 2 *[MPLS/0] 02:02:34, metric 1 Receive Now a static router is added to go to r7 from r1 taking this LSP as a next-hop. 10.0.9.7 is an IP on r7. The same route can be added to inet.0 automatically by using install active when configuring label-switch-path under mpls protocol. juniper@m10i> show route logical-system r1 10.0.9.7 inet.0: 14 destinations, 14 routes (14 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both 10.0.9.7/32 *[Static/5] 00:02:01 > to 10.0.4.13 via fe-0/1/0.0, label-switched-path r1-to-r7 juniper@m10i# run traceroute 10.0.9.7 logical-system r1 traceroute to 10.0.9.7 (10.0.9.7), 30 hops max, 40 byte packets 1 10.0.4.13 (10.0.4.13) 5.337 ms 39.758 ms 1.085 ms MPLS Label=299840 CoS=0 TTL=1 S=1 2 10.0.2.1 (10.0.2.1) 1.274 ms 1.098 ms 1.030 ms MPLS Label=299776 CoS=0 TTL=1 S=1 3 10.0.9.7 (10.0.9.7) 0.973 ms 1.021 ms 0.987 ms Area 10 has routers R1, R2, R3 and R4. Later two are ABRs connecting to area 0. TED output on logical-system R1 in area 10 is as follows: juniper@m10i> show ted database extensive logical-system r1 TED database: 0 ISIS nodes 3 INET nodes NodeID: 10.0.6.1 Type: Rtr, Age: 31429 secs, LinkIn: 1, LinkOut: 1 Protocol: OSPF(0.0.0.1) To: 10.0.4.6-1, Local: 10.0.4.5, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 Color: 0 <none> Metric: 1 Static BW: 1000Mbps Reservable BW: 1000Mbps Available BW [priority] bps: [0] 1000Mbps [1] 1000Mbps [2] 1000Mbps [3] 1000Mbps [4] 1000Mbps [5] 1000Mbps [6] 1000Mbps [7] 1000Mbps Interface Switching Capability Descriptor(1): Switching type: Packet Encoding type: Packet Maximum LSP BW [priority] bps: [0] 1000Mbps [1] 1000Mbps [2] 1000Mbps [3] 1000Mbps [4] 1000Mbps [5] 1000Mbps [6] 1000Mbps [7] 1000Mbps NodeID: 10.0.6.2 Type: Rtr, Age: 31429 secs, LinkIn: 1, LinkOut: 1 Protocol: OSPF(0.0.0.1) To: 10.0.4.6-1, Local: 10.0.4.6, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 Color: 0 <none> Metric: 1 Static BW: 1000Mbps Reservable BW: 1000Mbps Available BW [priority] bps: [0] 1000Mbps [1] 1000Mbps [2] 1000Mbps [3] 1000Mbps [4] 1000Mbps [5] 1000Mbps [6] 1000Mbps [7] 1000Mbps Interface Switching Capability Descriptor(1): Switching type: Packet Encoding type: Packet Maximum LSP BW [priority] bps: [0] 1000Mbps [1] 1000Mbps [2] 1000Mbps [3] 1000Mbps [4] 1000Mbps [5] 1000Mbps [6] 1000Mbps [7] 1000Mbps NodeID: 10.0.4.6-1 Type: Net, Age: 269502 secs, LinkIn: 2, LinkOut: 2 Protocol: OSPF(0.0.0.1) To: 10.0.6.1, Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 Metric: 0 Interface Switching Capability Descriptor(1): Switching type: Packet Encoding type: Packet Maximum LSP BW [priority] bps: [0] 0bps [1] 0bps [2] 0bps [3] 0bps [4] 0bps [5] 0bps [6] 0bps [7] 0bps To: 10.0.6.2, Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 Metric: 0 Interface Switching Capability Descriptor(1): Switching type: Packet Encoding type: Packet Maximum LSP BW [priority] bps: [0] 0bps [1] 0bps [2] 0bps [3] 0bps [4] 0bps [5] 0bps [6] 0bps [7] 0bps Using, OSPF we have to enable traffic-engineering on Juniper that results in the creation of TED. With ISIS, TED is created automatically and the TED is as follows for area comprising of r1 to r4: juniper@m10i> show ted database logical-system r1 TED database: 8 ISIS nodes 3 INET nodes ID Type Age(s) LnkIn LnkOut Protocol m10i-r3.00(10.0.3.3) Rtr 300 2 2 IS-IS(1) To: m10i-r3.02, Local: 10.0.4.1, Remote: 0.0.0.0 Local interface index: 100, Remote interface index: 0 To: m10i-r3.03, Local: 10.0.4.13, Remote: 0.0.0.0 Local interface index: 98, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r3.02 Net 300 2 2 IS-IS(1) To: m10i-r2.00(10.0.6.2), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 To: m10i-r3.00(10.0.3.3), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r3.03 Net 300 2 2 IS-IS(1) To: m10i-r1.00(10.0.6.1), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 To: m10i-r3.00(10.0.3.3), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r4.00 --- 76617 1 0 m10i-r4.03 Net 300 1 2 IS-IS(1) To: m10i-r2.00(10.0.6.2), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 To: m10i-r4.00, Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r1.00(10.0.6.1) Rtr 300 2 2 IS-IS(1) To: m10i-r2.02, Local: 10.0.4.5, Remote: 0.0.0.0 Local interface index: 96, Remote interface index: 0 To: m10i-r3.03, Local: 10.0.4.14, Remote: 0.0.0.0 Local interface index: 97, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r2.00(10.0.6.2) Rtr 300 3 3 IS-IS(1) To: m10i-r2.02, Local: 10.0.4.6, Remote: 0.0.0.0 Local interface index: 115, Remote interface index: 0 To: m10i-r3.02, Local: 10.0.4.2, Remote: 0.0.0.0 Local interface index: 99, Remote interface index: 0 To: m10i-r4.03, Local: 10.0.4.10, Remote: 0.0.0.0 Local interface index: 103, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol m10i-r2.02 Net 300 2 2 IS-IS(1) To: m10i-r1.00(10.0.6.1), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 To: m10i-r2.00(10.0.6.2), Local: 0.0.0.0, Remote: 0.0.0.0 Local interface index: 0, Remote interface index: 0 Links:MPLS.0