What is difference in Routing Protocols and WAN Protocols like PPP & HDLC? However, Routing protocols are also configure in WAN Topology.
PPP & HDLC are encapsulations , Your Ipv4 Packet is going in PPP & HDLC Frame.
Serial links are not using Ethernet technology they use PPP & HDLC to take IP in L2 Frame.
Routing Protocols are used to exchange the Prefix/Routes among Routers eithers routers are connected to ethernet cable or serial cable.