
Installation and Operation Manual
Chapter
1 Introduction
ACE-3105, ACE-3205 Ver. 5.2
Functional Description
1-23
When PHP mode is disabled:
•
The receiving LER advertises an actual label value to the previous hop. This
label is used when packets are transmitted to the LER.
•
After the tunnel label is established, all the traffic coming from the previous
hop, arrive over the tunnel label. This specifically includes IP control traffic
(such as LDP, Ping, etc.) that is transmitted over a tunnel label and not as
raw IP.
•
PW traffic over MPLS must be received with two MPLS labels: tunnel and PW
label.
•
Every packet received with single label is forwarded to the host in order to
allow control (IP) traffic over the MPLS tunnel.
•
It is not possible to configure a PW connection without an ingress tunnel label
(for either dynamic or static mode)
•
Traffic received as raw IP works normally.
Figure
1-16. Label Advertising in PHP Mode
PHP is enabled by default, meaning that all the control traffic is expected to be
received as raw IP.
PHP mode settings affect only the ingress tunnel behavior when it is established
with LDP. They do not affect PWs configured for an IP-based PSN type (MPLSoIP,
UDPoIP).
The following diagram shows how PHP mode availability affects configuration: