Setting The Protocol Mtu With Frame Relay Encapsulation; Configuring Frame Relay Keepalives - Juniper JUNOS 10.1 - CONFIGURATION GUIDE 1-2010 Configuration Manual

To modify the default media MTU size for a physical interface, include the
statement at the
If you change the size of the media MTU, you must ensure that the size is equal to
or greater than the sum of the protocol MTU and the encapsulation overhead. You
can include the
For more information, see "Setting the Protocol MTU with Frame Relay Encapsulation"
on page 385.

Setting the Protocol MTU with Frame Relay Encapsulation

For each interface, you can configure an interface-specific MTU by including the
statement at the
to modify this MTU for a particular protocol family, include the
You can include this statement at the following hierarchy levels:
For Frame Relay encapsulation, the default protocol MTU is 4470 bytes.
If you increase the size of the protocol MTU, you must ensure that the size of the
media MTU is equal to or greater than the sum of the protocol MTU and the
encapsulation overhead. (You configure the media MTU by including the
statement at the
"Configuring the Media MTU on Frame Relay Interfaces" on page 384.)
When the family is
1500 bytes and have 4 to 12 bytes of overhead.

Configuring Frame Relay Keepalives

By default, physical interfaces configured with Cisco High-level Data Link Control
(HDLC) or Point-to-Point Protocol (PPP) encapsulation send keepalive packets at
10-second intervals. The Frame Relay term for keepalives is Local Management
Interface (LMI) packets; note that the JUNOS Software supports both ANSI T1.617
Annex D LMIs and ITU Q933 Annex A LMIs.
[edit interfaces interface-name]
[edit interfaces interface-name]
mtu bytes;
mtu statement at the following hierarchy levels:
[edit interfaces interface-name unit logical-unit-number family family]
[edit logical-systems logical-system-name interfaces interface-name unit
logical-unit-number family family]
[edit interfaces interface interface-name]
mtu mtu;
[edit interfaces interface-name unit logical-unit-number family family]
[edit logical-systems logical-system-name interfaces interface-name unit
logical-unit-number family family]
[edit interfaces interface-name]
mpls , the default protocol MTU is 1488 bytes. MPLS packets are
Setting the Protocol MTU with Frame Relay Encapsulation
Chapter 16: Configuring Frame Relay
hierarchy level:
hierarchy level. If you need
statement:
mtu
hierarchy level, as discussed in
mtu
mtu
mtu
385