Example: ATM2 IQ-Based Layer 2 Circuit Configuration
Figure 1: ATM2 IQ-Based Layer 2 Circuit Topology Diagram
Figure 1 shows a similar network topology to our previous two examples. In this example, Routers PE1 and PE2 use ATM cell-relay mode on a CE-facing interface and ATM AAL5 mode on a second CE-facing interface.
On Router CE1, configure the ATM2 IQ interfaces to handle ATM traffic. Interface at-0/0/1 handles standard ATM traffic while interface at-0/0/2 handles AAL5 traffic.
Router CE1
On Router PE1, configure the ATM2 IQ-based CE-facing interfaces: one with ATM cell-relay mode CCC encapsulation and the other with ATM VC multiplexing CCC encapsulation. Also enable the corresponding Layer 2 circuit modes at the [edit chassis] hierarchy level. In this case, you must configure cell-relay mode on Physical Interface Card (PIC) 1 in Flexible PIC Concentrator (FPC) 0 and AAL5 mode on PIC 2 in FPC 1.
Establish your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for cell-relay mode traffic and a second VC for AAL5 traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.
Router PE1
On Router P0, configure LDP, MPLS, and OSPF on the interfaces connected to the PE routers. The core router provides the MPLS backbone needed to tunnel Layer 2 traffic from the ingress PR router to the egress PE router.
Router P0
On Router PE2, complete the Layer 2 circuit by configuring statements to match those previously set on Router PE1.
Configure the ATM2 IQ-based CE-facing interfaces: one with ATM cell-relay mode CCC encapsulation and the other with ATM VC multiplexing CCC encapsulation. Also enable the corresponding Layer 2 circuit modes at the [edit chassis] hierarchy level. In this case, you must configure cell-relay mode on PIC 1 in FPC 0 and AAL5 mode on PIC 2 in FPC 1.
Complete your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (Router PE1), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for cell-relay mode traffic and a second VC for AAL5 traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.
Router PE2
On Router CE2, configure the ATM2 IQ interfaces to handle ATM traffic. Interface at-1/0/1 handles standard ATM traffic while interface at-1/0/2 handles AAL5 traffic.
Router CE2
Verifying Your Work
To verify proper operation of Layer 2 circuits, use the following commands:
- ping mpls l2circuit interface interface-name
- ping mpls l2circuit virtual-circuit virtual-circuit-id neighbor ip-address
- show l2circuit connections
- Options: [brief] | [down] | [extensive] | [history] | [instance] | [local-site] | [remote-site] |[status] | [summary] | [up] | [up-down]
- show interfaces
- show route table l2circuit.0
- show ldp database l2circuit detail
This is what the operational command output looks like for cell-relay mode on Router PE1:
user@PE1> show l2circuit connections Layer-2 Circuit Connections:
Legend for connection status (St)
EI -- encapsulation invalid NP -- interface not present
MM -- mtu mismatch Dn -- down
EM -- encapsulation mismatch VC-Dn -- Virtual circuit Down
CM -- control-word mismatch Up -- operational
OL -- no outgoing label XX -- unknown
NC -- intf encaps not CCC/TCC
Legend for interface status
Up -- operational
Dn -- down
Neighbor: 10.255.17.4
Interface Type St Time last up # Up trans
at-0/1/0.0 (vc 32) rmt Up Jan 22 15:15:52 2003 1
Local interface: at-0/1/0.0, Status: Up, Encapsulation: ATM CELL (VC Mode)
Remote PE: 10.255.17.4, Negotiated control-word: Yes (Non-null)
Incoming label: 100000, Outgoing label: 100000
user@PE1> show route table l2circuit.0 detail
l2circuit.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
10.255.17.4:CtrlWord:9:32:Local/96 (1 entry, 1 announced)
*L2CKT Preference: 7
Next hop: via so-0/2/0.0 weight 1, selected
Label-switched-path PE1-PE2
Protocol next hop: 10.255.17.4 Indirect next hop: 85135e8 367
State: <Active Int>
Local AS: 69
Age: 2:34
Task: l2 circuit
Announcement bits (1): 0-LDP
AS path: I
VC Label 100000, MTU 0, cell-bundle size 80
10.255.17.4:CtrlWord:9:32:Remote/96 (1 entry, 1 announced)
*LDP Preference: 9
Next hop type: Discard
State: <Active Int>
Local AS: 69
Age: 28:11
Task: LDP
Announcement bits (1): 1-l2 circuit
AS path: I
VC Label 100000, MTU 0, cell-bundle size 80
user@PE1> show interfaces at-0/1/0.0 extensive
Logical interface at-0/1/0.0 (Index 66) (SNMP ifIndex 40) (Generation 4)
Flags: Point-To-Point SNMP-Traps Encapsulation: ATM-CCC-Cell-Relay
L2 circuit cell bundle size: 10 , bundle timeout: 125 usec, timeout count: 0
L2 circuit out-of-sequence count: 0
Traffic statistics:
[...]
user@PE1> show interfaces media at-0/1/0
Physical interface: at-0/1/0, Enabled, Physical link is Up
Interface index: 154, SNMP ifIndex: 50
Link-level type: ATM-CCC-Cell-Relay, MTU: 4482, Clocking: Internal, SONET mode,
L2 circuit mode: Cell, Speed: OC12, Loopback: None
[...]
user@PE1> show ldp database l2circuit detail
Input label database, 10.255.17.2:0--10.255.17.4:0
Label Prefix
100000 L2CKT CtrlWord ATM CELL (VC Mode) VC 32
Cell bundle size: 80
State: Active
Age: 9:48
Output label database, 10.255.17.2:0--10.255.17.4:0
Label Prefix
100000 L2CKT CtrlWord ATM CELL (VC Mode) VC 32
Cell bundle size: 80
State: Active
Age: 9:48
This is what the operational command output looks like on Router PE1 if AAL5 mode is used:
user@PE1> show l2circuit connections Layer-2 Circuit Connections:
Legend for connection status (St)
EI -- encapsulation invalid NP -- interface not present
MM -- mtu mismatch Dn -- down
EM -- encapsulation mismatch VC-Dn -- Virtual circuit Down
CM -- control-word mismatch Up -- operational
OL -- no outgoing label XX -- unknown
NC -- intf encaps not CCC/TCC
Legend for interface status
Up -- operational
Dn -- down
Neighbor: 10.255.17.4
Interface Type St Time last up # Up trans
at-1/2/0.0 (vc 32) rmt Up Feb 18 18:00:00 2003 1
Local interface: at-1/2/0.0, Status: Up, Encapsulation: ATM AAL5
Remote PE: 10.255.17.4, Negotiated control-word: Yes (Non-null)
Incoming label: 100016, Outgoing label: 100032
user@PE1> show interfaces media at-0/1/0
Physical interface: at-0/1/0, Enabled, Physical link is Up
Interface index: 154, SNMP ifIndex: 50
Link-level type: ATM-PVC, MTU: 4482, Clocking: Internal, SONET mode,
L2 circuit mode: AAL5, Speed: OC12, Loopback: None, Payload scrambler: Enabled
[...]
user@PE1> show interfaces at-1/2/0.0 extensive
Logical interface at-1/2/0.0 (Index 68) (SNMP ifIndex 40) (Generation 38)
Flags: Point-To-Point SNMP-Traps Encapsulation: ATM-CCC-VCMUX
L2 circuit out-of-sequence count: 0
Traffic statistics:[...]
