Testing PPPoX and L2TP Broadband Access Devices - Ixia

3. LNS Performance and
Scalability Test
3.1 Test Objective
The objective of this test is to emulate multiple LACs to
characterize the performance of LNS devices when
forwarding 32,000 PPPoX sessions including both control
and data plane traffic. The test is split into four phases,
namely:
• L2TP Tunnel setup, i.e. the rate at which the LNS can
terminate 32,000 tunnels.
• Tunneled session setup phase, i.e. the rate at which the
LACs can initiate 16k L2TP tunnels with or without
PAP/Chap authentication.
• PPPoX session establishment through L2TP tunnels.
• Data plane and keep-alive traffic generation (IMIX and
fixed frame sizes at 100% utilization).
3.3 Input Parameters
The primary input parameters for each phase include:
• PPPoXsession setup rate & latency – maximum,
minimum and average time and latency to establish all
sessions with either no authentication, PAP or CHAP
authentication.
• PPPoX interfaces, VLANs and domain groups for access
and network ports.
• L2TP sessions per tunnel, Hello Request intervals and
L2TP data plane options (e.g. UDP source and
destination ports).
• Traffic generation – upstream/downstream/bi-directional
for stateless L3/L4 traffic (IMIX or fixed frame
distributions).
• Session teardown rate.
3.2 Setup
In this test, Test tool emulates multiple LACs creating up to
32,000 L2TP tunnels and then running PPPoX session and
data traffic over those tunnels. As depicted in Figure 8,
either Ixia Ethernet or ATM ports may be used to simulate
the number of subscribers on the access side of the LNS.
The network side of the LNS is also connected to either Ixia
ATM or Ethernet ports to receive or generate IP traffic.
Access Side
- PPPoEoL2TP
- PPPoEo802.1qoL2TP
- PPPoAoL2TP
- PPPoAoL2TPoA
LNS
Network Side
- IP (Ethernet, VLAN or
ATM RFC 1483)
10/100/1000 Ethernet
Or OC3/OC12 ATM
10/100/1000 Ethernet
Or OC3/OC12 ATM
10/100/1000 Ethernet
Or OC3/OC12 ATM
Figure 8: PPPoX client emulation setup
8 Copyright © Ixia, 2004 PoE Test Plan