Provide Tier 3 support for diverse network environments including Cisco, Fortinet, Palo Alto, ADTRAN, Juniper, Meraki, and HP/Dell switches. Troubleshoot advanced routing protocols: OSPF, EIGRP, BGP, MPLS, DMVPN. Support SD-WAN platforms (Cisco Viptela, Ecessa, Vergx) and wireless LAN controllers. Configure and troubleshoot voice services: SIP, PRI, Hosted PBX, TDM/IP interworking, Fax over IP.