Configure the Encapsulation on a Physical Interface

[Contents] [Prev] [Next] [Index] [Report an Error]

Configure the Encapsulation on a Physical Interface
The physical interface encapsulation can be one of the following:

Point-to-Point Protocol (PPP)—Defined in RFC 1661, The Point-to-Point Protocol (PPP) for the Transmission of Multiprotocol Datagrams over Point-to-Point Links. PPP is the default encapsulation type for physical interfaces. E1, E3, SONET, T1, and T3 interfaces can use PPP encapsulation. Two related versions are supported:

Circuit cross-connect (CCC) version (ppp-ccc)—The logical interfaces do not require an encapsulation statement. When you use this encapsulation type, you can configure the family ccc only.

Translational cross-connect (TCC) version (ppp-tcc)—Similar to CCC and has the same configuration restrictions, but used for circuits with different media on either side of the connection.

ATM Cell Relay—Connects two remote virtual circuits or ATM physical interfaces with a label-switched path (LSP). Traffic on the circuit is ATM cells.

You can configure an ATM 1 PIC to use cell-relay accumulation mode (CAM). In this mode, the incoming cells (1 to 8 cells) are packaged into a single packet and forwarded to the label-switched path (LSP). Cell-relay accumulation mode is not supported on ATM 2 PICs. You configure CAM as shown in the following example:
[edit chassis]
fpc 1 {
    pic 0 {
        atm-cell-relay-accumulation;
    }
}
For more information, see the JUNOS Internet Software Configuration Guide: Getting Started.

ATM PVC—Defined in RFC 1483, Multiprotocol Encapsulation over ATM Adaptation Layer 5. When you configure physical ATM interfaces with ATM PVC encapsulation, you can configure the logical interfaces with any of the ATM encapsulations listed in Configure PPP Challenge Handshake Authentication Protocol.

Ethernet over ATM—Allows ATM interfaces to connect to devices that support only bridged-mode protocol data units (PDUs).

Cisco HDLC—E1, E3, SONET, T1, and T3 interfaces can use Cisco HDLC encapsulation. Two related versions are supported:

CCC version (cisco-hdlc-ccc)—The logical interfaces do not require an encapsulation statement. When you use this encapsulation type, you can configure the family ccc only.

TCC version (cisco-hdlc-tcc)—Similar to CCC and has the same configuration restrictions, but used for circuits with different media on either side of the connection.

Ethernet Cross-Connect—Ethernet interfaces without VLAN tagging can use Ethernet CCC encapsulation. Two related versions are supported:

CCC version (ethernet-ccc)—Ethernet interfaces with standard Tag Protocol ID (TPID) tagging can use Ethernet CCC encapsulation. On M-series routers, one-port Gigabit Ethernet, two-port Gigabit Ethernet, four-port Gigabit Ethernet, and four-port Fast Ethernet PICs can use Ethernet CCC encapsulation. On T-series platforms, one-port Gigabit Ethernet and two-port Gigabit Ethernet PICs installed in FPC2 can use Ethernet CCC encapsulation. When you use this encapsulation type, you can configure the family ccc only.

TCC version (ethernet-tcc)—Similar to CCC, but used for circuits with different media on either side of the connection. One-port Gigabit Ethernet, two-port Gigabit Ethernet, four-port Gigabit Ethernet, and four-port Fast Ethernet PICs can use Ethernet TCC encapsulation. Ethernet TCC is currently not supported on the T-series platforms.

Frame Relay—Defined in RFC 1490, Multiprotocol Interconnect over Frame Relay. E1, E3, link services, SONET, T1, and T3 interfaces can use Frame Relay encapsulation. Two related versions are supported:

CCC version (frame-relay-ccc)—The same as standard Frame Relay for DLCIs 0 through 511. DLCIs 512 through 1022 are dedicated to CCC, and the logical interface must also have frame-relay-ccc encapsulation. When you use this encapsulation type, you can configure the family ccc only.

TCC version (frame-relay-tcc)—Similar to Frame Relay CCC and has the same configuration restrictions, but is used for circuits with different media on either side of the connection.

Multilink Frame Relay (MLFR) User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) (multilink-frame-relay-uni-nni)—Link services interfaces functioning as FRF.16 bundles can use multilink Frame Relay UNI NNI encapsulation. This encapsulation is also used on link services interfaces' constituent T1, E1, or NxDS-0 interfaces.

VLAN Circuit Cross-Connect (CCC)—Ethernet interfaces with virtual local area network (VLAN) tagging enabled can use VLAN CCC encapsulation. VLAN CCC encapsulation supports TPID 0x8100 only. When you use this encapsulation type, you can configure the family ccc only.

Extended VLAN Cross-Connect—Gigabit Ethernet interfaces with Virtual Local Area Network (VLAN) tagging enabled can use extended VLAN cross-connect encapsulation. Two related versions of extended VLAN cross-connect are supported:

CCC version (extended-vlan-ccc)—Ethernet interfaces with 802.1Q tagging can use extended VLAN CCC encapsulation. (Ethernet interfaces with standard TPID tagging can use VLAN CCC encapsulation.) Extended VLAN CCC encapsulation supports TPIDs 0x8100, 0x9100, and 0x9901.

Extended VLAN CCC is not supported on four-port Gigabit Ethernet PICs. When you use this encapsulation type, you can configure the family ccc only.

TCC version (extended-vlan-tcc)—Similar to CCC, but used for circuits with different media on either side of the connection. One-port Gigabit Ethernet, two-port Gigabit Ethernet, four-port Gigabit Ethernet, and four-port Fast Ethernet PICs can use Extended Ethernet TCC encapsulation. Extended Ethernet TCC is currently not supported on the T-series platforms.

To configure the encapsulation on a physical interface, include the encapsulation statement at the [edit interfaces interface-name] hierarchy level:
[edit interfaces interface-name] 
encapsulation (atm-ccc-cell-relay | atm-pvc | cisco-hdlc | cisco-hdlc-ccc | cisco-hdlc-tcc | ethernet-ccc 

| ethernet-tcc | ethernet-over-atm | frame-relay | frame-relay-ccc | frame-relay-tcc | ppp | ppp-ccc | 
ppp-tcc | vlan-ccc | extended-vlan-ccc | extended-vlan-tcc); 
When you configure a point-to-point encapsulation (such as PPP or Cisco HDLC) on a physical interface, the physical interface can have only one logical interface (that is, only one unit statement) associated with it. When you configure a multipoint encapsulation (such as Frame Relay), the physical interface can have multiple logical units, and the units can be either point-to-point or multipoint.

Ethernet interfaces in VLAN mode can have multiple logical interfaces. For encapsulation type vlan-ccc, VLAN IDs from 1 through 511 are reserved for normal VLANs, and VLAN IDs from 512 through 1023 are reserved for CCC VLANs. For encapsulation type extended-vlan-ccc, all VLAN IDs from 1 through 4094 are valid. VLAN ID 0 is reserved for tagging the priority of frames. For more information, see Configure 802.1Q VLANs. Ethernet CCC encapsulation for Ethernet interfaces with standard TPID tagging requires that the physical interface have only a single logical interface.

When you configure a TCC encapsulation, some modifications are needed to handle VPN connections over unlike Layer 2 and Layer 2.5 links and terminate the Layer 2 and Layer 2.5 protocol locally. The router performs the following media-specific changes:

PPP TCC—Both Link Control Protocol (LCP) and Network Control Protocol (NCP) are terminated on the router. Internet Protocol Control Protocol (IPCP) IP address negotiation is not supported. The JUNOS software strips all PPP encapsulation data from incoming frames before forwarding them. For output, the next hop is changed to PPP encapsulation.

Cisco HDLC TCC—Keepalive processing is terminated on the router. The JUNOS software strips all Cisco HDLC encapsulation data from incoming frames before forwarding them. For output, the next hop is changed to Cisco HDLC encapsulation.

Frame Relay TCC—All Local Management Interface (LMI) processing is terminated on the router. The JUNOS software strips all Frame Relay encapsulation data from incoming frames before forwarding them. For output, the next hop is changed to Frame Relay encapsulation.

ATM—Operation, Administration, and Maintenance (OAM) and Interim Local Management Interface (ILMI) processing is terminated at the router. Cell relay is not supported. The JUNOS software strips all ATM encapsulation data from incoming frames before forwarding them. For output, the next hop is changed to ATM encapsulation.

Example: Configure the Encapsulation on a Physical Interface

Configure PPP encapsulation on a SONET interface. The second and third family statements allow IS-IS and MPLS to run on the interface:
[edit interfaces]
so-7/0/0 {
    encapsulation ppp;
    unit 0 {
        point-to-point;
        family inet {
            address 192.168.1.113/32 {
                destination 192.168.1.114;
            }
        }
        family iso;
        family mpls;
    }
}

[Contents] [Prev] [Next] [Index] [Report an Error]