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softwire-name (Next Gen Services)



Hierarchy Level

Release Information

Statement introduced in Junos OS Release 19.3R2 on MX Series routers (MX240, MX480 and MX960) running Next Gen Services with the MX-SPC3 services card.


Configure a 6rd softwire concentrator. A 6rd softwire allows an IPv6 end user to send traffic over an IPv4 network to reach an IPv6 network. The softwire concentrator decapsulates IPv6 packets that were encapsulated in IPv4 packets by a software initiator at the customer edge WAN, and forwards the packets for IPv6 routing.


ipv4-prefix ipv4-prefixIPv4 prefix of the customer edge (CE) network.
mtu-v4 number-of-bytesThe size, in bytes, of the maximum transmission unit for IPv6 packets encapsulated in IPv4. Compute this as the maximum expected IPv4 packet size plus 20. Packets that are larger than the configured value are dropped.

Range: 576 through 9192

softwire-concentrator addressIPv4 address of a softwire concentrator. This is an IPv4 address independent of any interface and on a different prefix.
softwire-name v6rd-softwire-concentratorName of the softwire concentrator.
softwire-type v6rdSets softwire concentrator type to 6rd.
v6rd-prefix v6rd-prefixIPv6 prefix for the 6rd domain.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.