Because tunnel services interfaces are considered logical interfaces, you cannot configure
the MTU setting for the physical interface. This means you cannot include the mtu
statement at the [edit interfaces interface-name] hierarchy level for the following interface
types: generic routing encapsulation (gr-), IP-IP (ip-), loopback (lo-), link services (ls-),
multilink services (ml-), and multicast (pe-, pd-). You can, however, configure the protocol
MTU on tunnel interfaces, as described in “Setting the Protocol MTU” on page 65.
Encapsulation Overhead by Encapsulation Type
Table 15: Encapsulation Overhead by Encapsulation Type
Encapsulation Overhead (Bytes)Interface Encapsulation
21802.1Q/Ethernet 802.3
26802.1Q/Ethernet Subnetwork Access Protocol (SNAP)
18802.1Q/Ethernet version 2
4ATM Cell Relay
12ATM permanent virtual connection (PVC)
4Cisco HDLC
17Ethernet 802.3
4Ethernet circuit cross-connect (CCC) and virtual private
LAN service (VPLS)
32Ethernet over ATM
22Ethernet SNAP
18Ethernet translational cross-connect (TCC)
14Ethernet version 2
4Extended virtual local area network (VLAN) CCC and
VPLS
22Extended VLAN TCC
4Frame Relay
4PPP
4VLAN CCC
4VLAN VPLS
22VLAN TCC
Copyright © 2015, Juniper Networks, Inc.56
Network Interfaces for EX4300 Switches