L2TP
The BNG Blaster can emulate L2TPv2 (RFC2661) LNS servers to be able to test the L2TPv2 LAC functionality of the BNG device under test.
Configuration
Following an example with 30 L2TP LNS servers.
{
"interfaces": {
"network": {
"interface": "eth2",
"address": "10.0.0.1",
"gateway": "10.0.0.2",
"address-ipv6": "fc66:1337:7331:8::10",
"gateway-ipv6": "fc66:1337:7331:8::1"
},
"access": [
{
"interface": "eth1",
"outer-vlan-min": 1,
"outer-vlan-max": 4000,
"inner-vlan-min": 7,
"inner-vlan-max": 7,
"authentication-protocol": "PAP"
},
{
"interface": "eth1",
"outer-vlan-min": 1,
"outer-vlan-max": 4000,
"inner-vlan-min": 8,
"inner-vlan-max": 8,
"authentication-protocol": "CHAP"
}
]
},
"pppoe": {
"reconnect": true,
"discovery-timeout": 3,
"discovery-retry": 10
},
"ppp": {
"mru": 1492,
"authentication": {
"username": "blaster@l2tp.de",
"password": "test",
"timeout": 1,
"retry": 60
},
"lcp": {
"conf-request-timeout": 5,
"conf-request-retry": 30,
"keepalive-interval": 30,
"keepalive-retry": 3
},
"ipcp": {
"enable": true
},
"ip6cp": {
"enable": true
}
},
"access-line": {
"agent-remote-id": "DEU.RTBRICK.{session}",
"agent-circuit-id": "0.0.0.0/0.0.0.0 eth 0:{session}",
"rate-up": 1024,
"rate-down": 16384
},
"l2tp-server": [
{
"name": "LNS1",
"address": "10.0.0.11",
"secret": "test1",
"receive-window-size": 8
},
{
"name": "LNS2",
"address": "10.0.0.12",
"secret": "test2",
"receive-window-size": 8
},
{
"name": "LNS3",
"address": "10.0.0.13",
"secret": "test3",
"receive-window-size": 8
},
{
"name": "LNS4",
"address": "10.0.0.14",
"secret": "test4",
"receive-window-size": 8
},
{
"name": "LNS5",
"address": "10.0.0.15",
"secret": "test5",
"receive-window-size": 8
},
{
"name": "LNS6",
"address": "10.0.0.16",
"secret": "test6",
"receive-window-size": 8
},
{
"name": "LNS7",
"address": "10.0.0.17",
"secret": "test7",
"receive-window-size": 8
},
{
"name": "LNS8",
"address": "10.0.0.18",
"secret": "test8",
"receive-window-size": 8
},
{
"name": "LNS9",
"address": "10.0.0.19",
"secret": "test9",
"receive-window-size": 8
},
{
"name": "LNS10",
"address": "10.0.0.20",
"secret": "test10",
"receive-window-size": 8
},
{
"name": "LNS11",
"address": "10.0.0.21",
"secret": "test11",
"receive-window-size": 8
},
{
"name": "LNS12",
"address": "10.0.0.22",
"secret": "test12",
"receive-window-size": 8
},
{
"name": "LNS13",
"address": "10.0.0.23",
"secret": "test13",
"receive-window-size": 8
},
{
"name": "LNS14",
"address": "10.0.0.24",
"secret": "test14",
"receive-window-size": 8
},
{
"name": "LNS15",
"address": "10.0.0.25",
"secret": "test15",
"receive-window-size": 8
},
{
"name": "LNS16",
"address": "10.0.0.26",
"secret": "test16",
"receive-window-size": 8
},
{
"name": "LNS17",
"address": "10.0.0.27",
"secret": "test17",
"receive-window-size": 8
},
{
"name": "LNS18",
"address": "10.0.0.28",
"secret": "test18",
"receive-window-size": 8
},
{
"name": "LNS19",
"address": "10.0.0.29",
"secret": "test19",
"receive-window-size": 8
},
{
"name": "LNS20",
"address": "10.0.0.30",
"secret": "test20",
"receive-window-size": 8
},
{
"name": "LNS21",
"address": "10.0.0.31",
"secret": "test21",
"receive-window-size": 8
},
{
"name": "LNS22",
"address": "10.0.0.32",
"secret": "test22",
"receive-window-size": 8
},
{
"name": "LNS23",
"address": "10.0.0.33",
"secret": "test23",
"receive-window-size": 8
},
{
"name": "LNS24",
"address": "10.0.0.34",
"secret": "test24",
"receive-window-size": 8
},
{
"name": "LNS25",
"address": "10.0.0.35",
"secret": "test25",
"receive-window-size": 8
},
{
"name": "LNS26",
"address": "10.0.0.36",
"secret": "test26",
"receive-window-size": 8
},
{
"name": "LNS27",
"address": "10.0.0.37",
"secret": "test27",
"receive-window-size": 8
},
{
"name": "LNS28",
"address": "10.0.0.38",
"secret": "test28",
"receive-window-size": 8
},
{
"name": "LNS29",
"address": "10.0.0.39",
"secret": "test29",
"receive-window-size": 8
},
{
"name": "LNS30",
"address": "10.0.0.40",
"secret": "test30",
"receive-window-size": 8
}
],
"session-traffic": {
"autostart": true,
"ipv4-pps": 1
}
}
{ "l2tp-server": [] }
Attribute |
Description |
Default |
|---|---|---|
name |
Mandatory L2TP LNS server hostname (AVP 7) |
|
address |
Mandatory L2TP server address |
|
secret |
Tunnel secret |
|
receive-window-size |
Control messages receive window size |
16 |
max-retry |
Control messages max retry |
5 |
congestion-mode |
Control messages congestion mode |
default |
hello-interval |
Set hello interval |
30 |
data-control-priority |
Set the priority bit in the L2TP header for all non-IP data packets (LCP, IPCP, …) |
false |
data-length |
Set length bit for all data packets |
false |
data-offset |
Set offset bit with offset zero for all data packets |
false |
control-tos |
L2TP control traffic (SCCRQ, ICRQ, …) TOS priority |
0 |
data-control-tos |
Set the L2TP tunnel TOS priority (outer IPv4 header) for all non-IP data packets (LCP, IPCP, …) |
0 |
The BNG Blaster supports different congestion modes for the
reliable delivery of control messages. The default mode
is described in RFC2661 appendix A (Control Channel Slow Start and
Congestion Avoidance). The mode slow uses a fixed control window
size of 1 where aggressive sticks to max permitted based on peer
received window size.
Variable Data Header
The L2TP protocol allows different data header options resulting in variable header lengths. The most common options can be tested with just four servers as shown in the example below.
{
"l2tp-server": [
{
"name": "LNS1",
"address": "10.0.0.11",
"secret": "test1",
"receive-window-size": 8,
"congestion-mode": "default",
"data-control-priority": true
},
{
"name": "LNS2",
"address": "10.0.0.12",
"secret": "test2",
"receive-window-size": 8,
"congestion-mode": "default",
"data-control-priority": true,
"data-length": true
},
{
"name": "LNS3",
"address": "10.0.0.11",
"secret": "test3",
"receive-window-size": 8,
"congestion-mode": "default",
"data-control-priority": true,
"data-offset": true
},
{
"name": "LNS4",
"address": "10.0.0.12",
"secret": "test4",
"receive-window-size": 8,
"congestion-mode": "default",
"data-control-priority": true,
"data-length": true,
"data-offset": true
}
]
}
RFC5515
The Agent-Circuit-Id and Agent-Remote-Id AVP defined in RFC5515 is supported and stored for each session if received. Received CSUN messages are processed correctly and via the control socket, it is possible to send also CSURQ requests to the LAC.
L2TP Commands
The command session-info l2tp-tunnels provides
detailed information about L2TP tunnels.
$ sudo bngblaster-cli run.sock l2tp-tunnels
{
"status": "ok",
"code": 200,
"l2tp-tunnels": [
{
"state": "Established",
"server-name": "LNS1",
"server-address": "10.0.0.11",
"tunnel-id": 1,
"peer-tunnel-id": 50011,
"peer-name": "BNG",
"peer-address": "10.0.0.2",
"peer-vendor": "RtBrick, Inc.",
"secret": "test1",
"control-packets-rx": 102,
"control-packets-rx-dup": 0,
"control-packets-rx-out-of-order": 0,
"control-packets-tx": 102,
"control-packets-tx-retry": 0,
"data-packets-rx": 1406,
"data-packets-tx": 206
}
]
}
The l2tp-sessions command returns all L2TP sessions.
$ sudo bngblaster-cli run.sock l2tp-sessions
{
"status": "ok",
"code": 200,
"l2tp-sessions": [
{
"state": "Established",
"tunnel-id": 1,
"session-id": 1,
"peer-tunnel-id": 50011,
"peer-session-id": 32867,
"peer-proxy-auth-name": "blaster@l2tp.de",
"peer-called-number": "N/A",
"peer-calling-number": "N/A",
"peer-sub-address": "N/A",
"peer-tx-bps": 48000,
"peer-rx-bps": 1000,
"peer-ari": "DEU.RTBRICK.1",
"peer-aci": "0.0.0.0/0.0.0.0 eth 0:1",
"data-packets-rx": 79,
"data-packets-tx": 79,
"data-ipv4-packets-rx": 15,
"data-ipv4-packets-tx": 15
}
]
}
This output can be also filtered to return only sessions of a given tunnel.
sudo bngblaster-cli run.sock l2tp-sessions tunnel-id 1
It is also possible to display a single session.
$ sudo bngblaster-cli run.sock l2tp-sessions tunnel-id 1 session-id 1