%% You should probably cite rfc9465 instead of this I-D.
@techreport{ietf-pim-null-register-packing-08,
    number =    {draft-ietf-pim-null-register-packing-08},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-pim-null-register-packing/08/},
    author =    {Vikas Ramesh Kamath and Ramakrishnan Cokkanathapuram Sundaram and Raunak Banthia and Ananya Gopal},
    title =     {{PIM Null-Register packing}},
    pagetotal = 9,
    year =      2021,
    month =     mar,
    day =       22,
    abstract =  {In PIM-SM networks PIM Register messages are sent by the Designated Router (DR) to the Rendezvous Point (RP) to signal the presence of Multicast sources in the network. There are periodic PIM Null- Registers sent from the DR to the RP to keep the state alive at the RP as long as the source is active. The PIM Null-Register message carries information about a single Multicast source and group. This document defines a standard to send multiple multicast source and group information in a single PIM Null-Register message, in a packed format. This document also discusses the interoperability between the PIM routers which do not understand the packed message format with multiple multicast source and group details.},
}