L2TPv3 – Layer 2 Tunneling Protocol Version 3
L2TPv3 provides the capabilities to tunnel Layer 2 payload over IP network. When L2TPv3 is implemented, the physical interfaces that are connected to the customer’s network are used as tunnel ingress and egress interfaces. It is documented in RFC3931.
L2TP is comprised of two types of messages, control messages and data messages.Control messages are used in the establishment, maintenance, and clearing of control connections and sessions. These messages utilize a reliable control channel within L2TP to guarantee delivery. Data messages are used to encapsulate the L2 traffic being carried over the L2TP session. Unlike control messages, data messages are not re-transmitted when packet loss occurs.
L2TPv3 Header Format
The session identifier identifies the tunnel context at the decapsulating router. The session ID of 0 is reserved for use by the protocol. Static L2TPv3 sessions need manual configuration of session ID on the PE routers. However, for dynamic L2TPv3 tunnel setup, the session IDs can be chosen depending on the number of tunnels that are supported by the router in question.
The cookie contains the key for the L2TPv3 session. The cookie length can be configured on a router, but the default value for the cookie length is 4 bytes. When the originating and terminating routers are different platforms, the cookie length needs to be configured manually to be 4 bytes.
Pseudowire control encapsulation consists of 4 bytes and implements sequencing with the L2TPv3 tunnel. It uses only the first bit and bits 8 through 31. The value of the first bit defines if bits 8 through 31 contain a sequence number and if it needs to be updated.
L2TPv3 Components
Control Connection
An L2TP control connection is a reliable control channel that is used to establish, maintain, and release individual L2TP sessions as well as the control connection itself.
Control Message
Control channel messages are used for signalling between the two routers that are the endpoints of the L2TPv3 pseudowire. These endpoints can be referred to as L2TP Control Connection Endpoints – LCCEs. Control connection messages can be used by the LCCEs to setup the control connection itself, to establish L2TPv3 sessions, to indicate circuit status changes, to tear down sessions, to terminate the control connection, and to provide a keepalive mechanism.
Data Channel
The channel for L2TP-encapsulated data traffic that passes between two LCCEs over IP Network.
Data Message
Data channel messages, on the other hand, are the messages that actually carry the Layer-2 protocols and connections over the IP backbone.
Pseudowire (PW)
It is an emulated circuit as it traverses a IP network.There is one Pseudowire per L2TP Session.
Network Topology
We will use following topology to configure L2TPv3 and extend Layer2 network from R4 to R5 and from R6 to R7.
Configuring L2TPv3 Static/Manual Tunnels
R1 - Provider Edge Router connected to Customer Routers hostname R1 ! ip cef ! !! -- L2TP class implements a template for control channel -- !! !! -- parameters that can be applied to different pseudowire -- !! !! -- classes on the router -- !! l2tp-class L2TP-CLASS cookie size 4 ! !! -- Pseudowire class defines the session level parameters of -- !! !! -- the L2TPV3 sessions -- !! pseudowire-class PW-CLASS !! -- Data Encapsulation Protocol -- !! encapsulation l2tpv3 !! -- No signaling protocol for Static Tunnels -- !! protocol none !! -- Configure the Source Address of the Tunnel -- !! ip local interface Loopback0 ! interface Loopback0 ip address 10.1.1.1 255.255.255.255 ! interface FastEthernet0/0 ip address 10.1.13.1 255.255.255.0 ip ospf network point-to-point duplex full speed 100 ! interface FastEthernet0/1 description To Cust-A Site-1 R4 no ip address no cdp enable xconnect 10.1.1.2 101 encapsulation l2tpv3 manual pw-class PW-CLASS l2tp id 101 101 l2tp cookie local 4 1 l2tp cookie remote 4 1 l2tp hello L2TP-CLASS ! interface Serial1/0 description To Cust-B Site-1 R6 no ip address encapsulation ppp serial restart-delay 0 no cdp enable xconnect 10.1.1.2 102 encapsulation l2tpv3 manual pw-class PW-CLASS l2tp id 102 102 l2tp cookie local 4 1 l2tp cookie remote 4 1 l2tp hello L2TP-CLASS ! router ospf 1 network 10.1.0.0 0.0.255.255 area 0 ! R2 - Provider Edge Router connected to Customer Routers hostname R2 ! ip cef ! l2tp-class L2TP-CLASS cookie size 4 ! pseudowire-class PW-CLASS encapsulation l2tpv3 protocol none ip local interface Loopback0 ! interface Loopback0 ip address 10.1.1.2 255.255.255.255 ! interface FastEthernet0/0 ip address 10.1.23.2 255.255.255.0 ip ospf network point-to-point duplex full speed 100 ! interface FastEthernet0/1 description To Cust-A Site-2 R5 no ip address no cdp enable xconnect 10.1.1.1 101 encapsulation l2tpv3 manual pw-class PW-CLASS l2tp id 101 101 l2tp cookie local 4 1 l2tp cookie remote 4 1 l2tp hello L2TP-CLASS ! interface Serial1/0 description To Cust-B Site-2 R6 no ip address encapsulation ppp serial restart-delay 0 no cdp enable xconnect 10.1.1.1 102 encapsulation l2tpv3 manual pw-class PW-CLASS l2tp id 102 102 l2tp cookie local 4 1 l2tp cookie remote 4 1 l2tp hello L2TP-CLASS ! router ospf 1 network 10.1.0.0 0.0.255.255 area 0 ! R3 - Provider Core Network Router hostname R3 ! ip cef ! interface FastEthernet0/0 ip address 10.1.13.3 255.255.255.0 ip ospf network point-to-point duplex full speed 100 ! interface FastEthernet0/1 ip address 10.1.23.3 255.255.255.0 ip ospf network point-to-point duplex full speed 100 ! router ospf 1 network 10.1.0.0 0.0.255.255 area 0 ! R4 - Customer-A Site-1 Edge Router hostname R4 ! interface FastEthernet0/0 ip address 172.16.4.4 255.255.255.0 ! interface FastEthernet0/1 ip address 172.16.45.1 255.255.255.252 ! router eigrp 100 network 172.16.0.0 ! R5 - Customer-A Site-2 Edge Router hostname R5 ! interface FastEthernet0/0 ip address 172.16.5.5 255.255.255.0 ! interface FastEthernet0/1 ip address 172.16.45.2 255.255.255.252 ! router eigrp 100 network 172.16.0.0 ! R6 - Customer-B Site-1 Edge Router hostname R6 ! interface FastEthernet0/0 ip address 192.168.6.6 255.255.255.0 ! interface Serial1/0 ip address 192.168.67.1 255.255.255.252 encapsulation ppp serial restart-delay 0 ! router eigrp 100 network 192.168.0.0 0.0.255.255 ! R7 - Customer-B Site-2 Edge Router hostname R7 ! interface FastEthernet0/0 ip address 192.168.7.7 255.255.255.0 ! interface Serial1/0 ip address 192.168.67.2 255.255.255.252 encapsulation ppp serial restart-delay 0 ! router eigrp 100 network 192.168.0.0 0.0.255.255 !
Verification & Testing
R1#show ip route | beg Gate Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks C 10.1.1.1/32 is directly connected, Loopback0 O 10.1.1.2/32 [110/3] via 10.1.13.3, 00:11:24, FastEthernet0/0 C 10.1.13.0/24 is directly connected, FastEthernet0/0 L 10.1.13.1/32 is directly connected, FastEthernet0/0 O 10.1.23.0/24 [110/2] via 10.1.13.3, 00:11:24, FastEthernet0/0 R2#show ip route | beg Gate Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks O 10.1.1.1/32 [110/3] via 10.1.23.3, 00:11:35, FastEthernet0/0 C 10.1.1.2/32 is directly connected, Loopback0 O 10.1.13.0/24 [110/2] via 10.1.23.3, 00:11:45, FastEthernet0/0 C 10.1.23.0/24 is directly connected, FastEthernet0/0 L 10.1.23.2/32 is directly connected, FastEthernet0/0 R3#show ip route | beg Gate Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks O 10.1.1.1/32 [110/2] via 10.1.13.1, 00:11:54, FastEthernet0/0 O 10.1.1.2/32 [110/2] via 10.1.23.2, 00:11:54, FastEthernet0/1 C 10.1.13.0/24 is directly connected, FastEthernet0/0 L 10.1.13.3/32 is directly connected, FastEthernet0/0 C 10.1.23.0/24 is directly connected, FastEthernet0/1 L 10.1.23.3/32 is directly connected, FastEthernet0/1 R1#show l2tun tunnel all L2TP Tunnel Information Total tunnels 1 sessions 2 Tunnel id 4276657069 is up, remote id is 1806975601, 2 active sessions Locally initiated tunnel Tunnel state is established, time since change 00:12:34 Tunnel transport is IP (115) Remote tunnel name is R2 Internet Address 10.1.1.2, port 0 Local tunnel name is R1 Internet Address 10.1.1.1, port 0 L2TP class for tunnel is L2TP-CLASS Counters, taking last clear into account: 0 packets sent, 0 received 0 bytes sent, 0 received Last clearing of counters never Counters, ignoring last clear: 0 packets sent, 0 received 0 bytes sent, 0 received Control Ns 3, Nr 13 Local RWS 1024 (default), Remote RWS 1024 Control channel Congestion Control is disabled Tunnel PMTU checking disabled Retransmission time 1, max 1 seconds Unsent queuesize 0, max 0 Resend queuesize 0, max 1 Total resends 0, ZLB ACKs sent 12 Total out-of-order dropped pkts 0 Total out-of-order reorder pkts 0 Total peer authentication failures 0 Current no session pak queue check 0 of 5 Retransmit time distribution: 0 0 0 0 0 0 0 0 0 Control message authentication is disabled R2#show l2tun tunnel all L2TP Tunnel Information Total tunnels 1 sessions 2 Tunnel id 1806975601 is up, remote id is 4276657069, 2 active sessions Remotely initiated tunnel Tunnel state is established, time since change 00:13:47 Tunnel transport is IP (115) Remote tunnel name is R1 Internet Address 10.1.1.1, port 0 Local tunnel name is R2 Internet Address 10.1.1.2, port 0 L2TP class for tunnel is L2TP-CLASS Counters, taking last clear into account: 0 packets sent, 0 received 0 bytes sent, 0 received Last clearing of counters never Counters, ignoring last clear: 0 packets sent, 0 received 0 bytes sent, 0 received Control Ns 14, Nr 3 Local RWS 1024 (default), Remote RWS 1024 Control channel Congestion Control is disabled Tunnel PMTU checking disabled Retransmission time 1, max 1 seconds Unsent queuesize 0, max 0 Resend queuesize 0, max 1 Total resends 0, ZLB ACKs sent 2 Total out-of-order dropped pkts 0 Total out-of-order reorder pkts 0 Total peer authentication failures 0 Current no session pak queue check 0 of 5 Retransmit time distribution: 0 0 0 0 0 0 0 0 0 Control message authentication is disabled R1#show l2tun session all L2TP Session Information Total tunnels 1 sessions 2 Session id 102 is up, logical session id 65548, tunnel id 4276657069 Remote session id is 102, remote tunnel id 1806975601 Locally initiated session Unique ID is 4 Session Layer 2 circuit, type is PPP, name is Serial1/0 Session vcid is 102 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 0 Remote tunnel name is Internet address is 10.1.1.2 Local tunnel name is Internet address is 10.1.1.1 IP protocol 115 Session is manually signaled Session state is established, time since change 00:15:06 408 Packets sent, 406 received 20885 Bytes sent, 20891 received Last clearing of counters never Counters, ignoring last clear: 408 Packets sent, 406 received 20885 Bytes sent, 20891 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified Session cookie information: local cookie, size 4 bytes, value 00 00 00 01 remote cookie, size 4 bytes, value 00 00 00 01 FS cached header information: encap size = 28 bytes 45000014 00000000 ff73a572 0a010101 0a010102 00000066 00000001 Sequencing is off Conditional debugging is disabled SSM switch id is 8200, SSM segment id is 16405 Session id 101 is up, logical session id 32778, tunnel id 4276657069 Remote session id is 101, remote tunnel id 1806975601 Locally initiated session Unique ID is 1 Session Layer 2 circuit, type is Ethernet, name is FastEthernet0/1 Session vcid is 101 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 0 Remote tunnel name is Internet address is 10.1.1.2 Local tunnel name is Internet address is 10.1.1.1 IP protocol 115 Session is manually signaled Session state is established, time since change 00:15:06 315 Packets sent, 310 received 26766 Bytes sent, 26400 received Last clearing of counters never Counters, ignoring last clear: 315 Packets sent, 310 received 26766 Bytes sent, 26400 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified Session cookie information: local cookie, size 4 bytes, value 00 00 00 01 remote cookie, size 4 bytes, value 00 00 00 01 FS cached header information: encap size = 28 bytes 45000014 00000000 ff73a572 0a010101 0a010102 00000065 00000001 Sequencing is off Conditional debugging is disabled SSM switch id is 4102, SSM segment id is 12308 R2#show l2tun session all L2TP Session Information Total tunnels 1 sessions 2 Session id 102 is up, logical session id 65548, tunnel id 1806975601 Remote session id is 102, remote tunnel id 4276657069 Locally initiated session Unique ID is 4 Session Layer 2 circuit, type is PPP, name is Serial1/0 Session vcid is 102 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 0 Remote tunnel name is Internet address is 10.1.1.1 Local tunnel name is Internet address is 10.1.1.2 IP protocol 115 Session is manually signaled Session state is established, time since change 00:15:56 433 Packets sent, 427 received 22397 Bytes sent, 21989 received Last clearing of counters never Counters, ignoring last clear: 433 Packets sent, 427 received 22397 Bytes sent, 21989 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified Session cookie information: local cookie, size 4 bytes, value 00 00 00 01 remote cookie, size 4 bytes, value 00 00 00 01 FS cached header information: encap size = 28 bytes 45000014 00000000 ff73a572 0a010102 0a010101 00000066 00000001 Sequencing is off Conditional debugging is disabled SSM switch id is 8200, SSM segment id is 16405 Session id 101 is up, logical session id 32778, tunnel id 1806975601 Remote session id is 101, remote tunnel id 4276657069 Locally initiated session Unique ID is 1 Session Layer 2 circuit, type is Ethernet, name is FastEthernet0/1 Session vcid is 101 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 0 Remote tunnel name is Internet address is 10.1.1.1 Local tunnel name is Internet address is 10.1.1.2 IP protocol 115 Session is manually signaled Session state is established, time since change 00:15:56 329 Packets sent, 330 received 27997 Bytes sent, 28095 received Last clearing of counters never Counters, ignoring last clear: 329 Packets sent, 330 received 27997 Bytes sent, 28095 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified Session cookie information: local cookie, size 4 bytes, value 00 00 00 01 remote cookie, size 4 bytes, value 00 00 00 01 FS cached header information: encap size = 28 bytes 45000014 00000000 ff73a572 0a010102 0a010101 00000065 00000001 Sequencing is off Conditional debugging is disabled SSM switch id is 4102, SSM segment id is 12307
!! -- Customer A Site-1 router can reach Site-2 Router WAN IP -- !! !! -- through L2TPV3 tunneling over Service Provider IP network -- !! R4#ping 172.16.45.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.45.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 96/103/108 ms !! -- Customer A Site-1 Router would see Site-2 Router as -- !! !! -- directly connected as they would be directly connected -- !! !! -- on a layer 2 network -- !! R4#ping 172.16.45.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.45.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 96/103/108 ms R4#show cdp neighbors Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone, D - Remote, C - CVTA, M - Two-port Mac Relay Device ID Local Intrfce Holdtme Capability Platform Port ID R5 Fas 0/1 145 R 7206VXR Fas 0/1 R4#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 172.16.45.2 Fa0/1 10 00:17:52 1605 5000 0 3 R4#show ip route | beg Gate Gateway of last resort is not set 172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks C 172.16.4.0/24 is directly connected, FastEthernet0/0 L 172.16.4.4/32 is directly connected, FastEthernet0/0 D 172.16.5.0/24 [90/30720] via 172.16.45.2, 00:18:16, FastEthernet0/1 C 172.16.45.0/30 is directly connected, FastEthernet0/1 L 172.16.45.1/32 is directly connected, FastEthernet0/1 R5#show ip route | beg Gate Gateway of last resort is not set 172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks D 172.16.4.0/24 [90/30720] via 172.16.45.1, 00:22:24, FastEthernet0/1 C 172.16.5.0/24 is directly connected, FastEthernet0/0 L 172.16.5.5/32 is directly connected, FastEthernet0/0 C 172.16.45.0/30 is directly connected, FastEthernet0/1 L 172.16.45.2/32 is directly connected, FastEthernet0/1 R4#ping 172.16.5.5 source 172.16.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.5.5, timeout is 2 seconds: Packet sent with a source address of 172.16.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 84/95/100 ms R4#traceroute 172.16.5.5 source 172.16.4.4 Type escape sequence to abort. Tracing the route to 172.16.5.5 VRF info: (vrf in name/id, vrf out name/id) 1 172.16.45.2 100 msec * 92 msec !! -- Customer B Site-1 router can reach Site-2 Router WAN IP -- !! !! -- through L2TPV3 tunneling over Service Provider IP network -- !! R6#ping 192.168.67.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.67.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 96/105/116 ms R6#show cdp neighbors Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone, D - Remote, C - CVTA, M - Two-port Mac Relay Device ID Local Intrfce Holdtme Capability Platform Port ID R7 Ser 1/0 136 R 7206VXR Ser 1/0 R6#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 192.168.67.2 Se1/0 14 00:22:46 140 840 0 3 R6#show ip route | beg Gate Gateway of last resort is not set 192.168.6.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.6.0/24 is directly connected, FastEthernet0/0 L 192.168.6.6/32 is directly connected, FastEthernet0/0 D 192.168.7.0/24 [90/2172416] via 192.168.67.2, 00:22:57, Serial1/0 192.168.67.0/24 is variably subnetted, 3 subnets, 2 masks C 192.168.67.0/30 is directly connected, Serial1/0 L 192.168.67.1/32 is directly connected, Serial1/0 C 192.168.67.2/32 is directly connected, Serial1/0 R6#ping 192.168.7.7 source 192.168.6.6 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.7.7, timeout is 2 seconds: Packet sent with a source address of 192.168.6.6 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 96/103/112 ms R6#traceroute 192.168.7.7 source 192.168.6.6 Type escape sequence to abort. Tracing the route to 192.168.7.7 VRF info: (vrf in name/id, vrf out name/id) 1 192.168.67.2 92 msec * 104 msec
Configuring L2TPv3 Dynamic Tunnels
The only differences are in the configuration of the pseudowire class or template as well as the attachment circuit configuration. In comparison to implementation of static/manual L2TPV3 tunnel configuration, Dynamic L2TPV3 Tunnel configuration is the configuration of a protocol for signalling the control channel parameters. We used “protocol none” (no signalling protocol) in pseudowire-class with static/manual tunnel configuration. We will not use this command with Dynamic tunnel configuration. By default it will use L2TP for signalling here.
R1 - Provider Edge Router connected to Customer Routers hostname R1 ! ip cef ! pseudowire-class PW-CLASS encapsulation l2tpv3 ip local interface Loopback0 ! interface Loopback0 ip address 10.1.1.1 255.255.255.255 ! interface FastEthernet0/0 ip address 10.1.13.1 255.255.255.0 ip ospf network point-to-point ! interface FastEthernet0/1 description To Cust-A Site-1 R4 no ip address no cdp enable xconnect 10.1.1.2 101 pw-class PW-CLASS ! interface Serial1/0 description To Cust-B Site-1 R6 no ip address encapsulation ppp no cdp enable xconnect 10.1.1.2 102 pw-class PW-CLASS ! router ospf 1 network 10.1.0.0 0.0.255.255 area 0 ! R2 - Provider Edge Router connected to Customer Routers hostname R2 ! ip cef ! pseudowire-class PW-CLASS encapsulation l2tpv3 ip local interface Loopback0 ! interface Loopback0 ip address 10.1.1.2 255.255.255.255 ! interface FastEthernet0/0 ip address 10.1.23.2 255.255.255.0 ip ospf network point-to-point ! interface FastEthernet0/1 description To Cust-A Site-2 R5 no ip address no cdp enable xconnect 10.1.1.1 101 pw-class PW-CLASS ! interface Serial1/0 description To Cust-B Site-2 R7 no ip address encapsulation ppp no cdp enable xconnect 10.1.1.1 102 pw-class PW-CLASS ! router ospf 1 network 10.1.0.0 0.0.255.255 area 0 !
Verification & Testing
R1#show l2tun tunnel all L2TP Tunnel Information Total tunnels 1 sessions 2 Tunnel id 1776971907 is up, remote id is 329857833, 2 active sessions Remotely initiated tunnel Tunnel state is established, time since change 00:04:40 Tunnel transport is IP (115) Remote tunnel name is R2 Internet Address 10.1.1.2, port 0 Local tunnel name is R1 Internet Address 10.1.1.1, port 0 L2TP class for tunnel is l2tp_default_class Counters, taking last clear into account: 235 packets sent, 232 received 15766 bytes sent, 15568 received Last clearing of counters never Counters, ignoring last clear: 235 packets sent, 232 received 15766 bytes sent, 15568 received Control Ns 5, Nr 11 Local RWS 1024 (default), Remote RWS 1024 Control channel Congestion Control is disabled Tunnel PMTU checking disabled Retransmission time 1, max 1 seconds Unsent queuesize 0, max 0 Resend queuesize 0, max 2 Total resends 0, ZLB ACKs sent 8 Total out-of-order dropped pkts 0 Total out-of-order reorder pkts 0 Total peer authentication failures 0 Current no session pak queue check 0 of 5 Retransmit time distribution: 0 0 0 0 0 0 0 0 0 Control message authentication is disabled R1#show l2tun session all L2TP Session Information Total tunnels 1 sessions 2 Session id 1211541847 is up, logical session id 98324, tunnel id 1776971907 Remote session id is 132911511, remote tunnel id 329857833 Remotely initiated session Unique ID is 4 Session Layer 2 circuit, type is PPP, name is Serial1/0 Session vcid is 102 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 1898000001 Remote tunnel name is R2 Internet address is 10.1.1.2 Local tunnel name is R1 Internet address is 10.1.1.1 IP protocol 115 Session is L2TP signaled Session state is established, time since change 00:05:01 142 Packets sent, 142 received 7563 Bytes sent, 7583 received Last clearing of counters never Counters, ignoring last clear: 142 Packets sent, 142 received 7563 Bytes sent, 7583 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified No session cookie information available FS cached header information: encap size = 24 bytes 45000014 00000000 ff73a572 0a010101 0a010102 07ec1197 Sequencing is off Conditional debugging is disabled SSM switch id is 8198, SSM segment id is 12312 Session id 2531932146 is up, logical session id 65558, tunnel id 1776971907 Remote session id is 490732246, remote tunnel id 329857833 Remotely initiated session Unique ID is 1 Session Layer 2 circuit, type is Ethernet, name is FastEthernet0/1 Session vcid is 101 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 1898000002 Remote tunnel name is R2 Internet address is 10.1.1.2 Local tunnel name is R1 Internet address is 10.1.1.1 IP protocol 115 Session is L2TP signaled Session state is established, time since change 00:05:01 109 Packets sent, 106 received 9059 Bytes sent, 8841 received Last clearing of counters never Counters, ignoring last clear: 109 Packets sent, 106 received 9059 Bytes sent, 8841 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified No session cookie information available FS cached header information: encap size = 24 bytes 45000014 00000000 ff73a572 0a010101 0a010102 1d3ffad6 Sequencing is off Conditional debugging is disabled SSM switch id is 4100, SSM segment id is 16409 R2#show l2tun tunnel all L2TP Tunnel Information Total tunnels 1 sessions 2 Tunnel id 329857833 is up, remote id is 1776971907, 2 active sessions Locally initiated tunnel Tunnel state is established, time since change 00:06:02 Tunnel transport is IP (115) Remote tunnel name is R1 Internet Address 10.1.1.1, port 0 Local tunnel name is R2 Internet Address 10.1.1.2, port 0 L2TP class for tunnel is l2tp_default_class Counters, taking last clear into account: 295 packets sent, 297 received 19736 bytes sent, 19872 received Last clearing of counters never Counters, ignoring last clear: 295 packets sent, 297 received 19736 bytes sent, 19872 received Control Ns 13, Nr 5 Local RWS 1024 (default), Remote RWS 1024 Control channel Congestion Control is disabled Tunnel PMTU checking disabled Retransmission time 1, max 1 seconds Unsent queuesize 0, max 0 Resend queuesize 0, max 3 Total resends 0, ZLB ACKs sent 4 Total out-of-order dropped pkts 0 Total out-of-order reorder pkts 0 Total peer authentication failures 0 Current no session pak queue check 0 of 5 Retransmit time distribution: 0 0 0 0 0 0 0 0 0 Control message authentication is disabled R2#show l2tun session all L2TP Session Information Total tunnels 1 sessions 2 Session id 132911511 is up, logical session id 65548, tunnel id 329857833 Remote session id is 1211541847, remote tunnel id 1776971907 Locally initiated session Unique ID is 4 Session Layer 2 circuit, type is PPP, name is Serial1/0 Session vcid is 102 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 1898000001 Remote tunnel name is R1 Internet address is 10.1.1.1 Local tunnel name is R2 Internet address is 10.1.1.2 IP protocol 115 Session is L2TP signaled Session state is established, time since change 00:06:16 175 Packets sent, 174 received 9117 Bytes sent, 9035 received Last clearing of counters never Counters, ignoring last clear: 175 Packets sent, 174 received 9117 Bytes sent, 9035 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified No session cookie information available FS cached header information: encap size = 24 bytes 45000014 00000000 ff73a572 0a010102 0a010101 4836a957 Sequencing is off Conditional debugging is disabled SSM switch id is 8198, SSM segment id is 12310 Session id 490732246 is up, logical session id 32776, tunnel id 329857833 Remote session id is 2531932146, remote tunnel id 1776971907 Locally initiated session Unique ID is 1 Session Layer 2 circuit, type is Ethernet, name is FastEthernet0/1 Session vcid is 101 Circuit state is UP Local circuit state is UP Remote circuit state is UP Call serial number is 1898000002 Remote tunnel name is R1 Internet address is 10.1.1.1 Local tunnel name is R2 Internet address is 10.1.1.2 IP protocol 115 Session is L2TP signaled Session state is established, time since change 00:06:16 132 Packets sent, 135 received 11203 Bytes sent, 11421 received Last clearing of counters never Counters, ignoring last clear: 132 Packets sent, 135 received 11203 Bytes sent, 11421 received Receive packets dropped: out-of-order: 0 other: 0 total: 0 Send packets dropped: exceeded session MTU: 0 other: 0 total: 0 DF bit off, ToS reflect disabled, ToS value 0, TTL value 255 Sending UDP checksums are disabled Received UDP checksums are verified No session cookie information available FS cached header information: encap size = 24 bytes 45000014 00000000 ff73a572 0a010102 0a010101 96ea37f2 Sequencing is off Conditional debugging is disabled SSM switch id is 4100, SSM segment id is 16407
R4#ping 172.16.45.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.45.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 92/105/116 ms R4#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 172.16.45.2 Fa0/1 14 00:07:29 192 1152 0 3 R4#show ip route | beg Gate Gateway of last resort is not set 172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks C 172.16.4.0/24 is directly connected, FastEthernet0/0 L 172.16.4.4/32 is directly connected, FastEthernet0/0 D 172.16.5.0/24 [90/30720] via 172.16.45.2, 00:07:45, FastEthernet0/1 C 172.16.45.0/30 is directly connected, FastEthernet0/1 L 172.16.45.1/32 is directly connected, FastEthernet0/1 R6#ping 192.168.67.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.67.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 96/104/116 ms R6#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 192.168.67.2 Se1/0 12 00:08:43 119 714 0 3 R6#show ip route | beg Gate Gateway of last resort is not set 192.168.6.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.6.0/24 is directly connected, FastEthernet0/0 L 192.168.6.6/32 is directly connected, FastEthernet0/0 D 192.168.7.0/24 [90/2172416] via 192.168.67.2, 00:08:50, Serial1/0 192.168.67.0/24 is variably subnetted, 3 subnets, 2 masks C 192.168.67.0/30 is directly connected, Serial1/0 L 192.168.67.1/32 is directly connected, Serial1/0 C 192.168.67.2/32 is directly connected, Serial1/0
