Forum of Layer 2 Layer 3 technologies

URL Filtering in PALO ALTO requires configuration of below things,  1 . Interface/Zone configuration  2 . Static route Configuration .  3 . NAT Configuration  4 . URL Filtering Configuration  5 . Security Policy Configuration  Topology : Interface , Router Config: 1 . Configure the interface which is connected to linux vm in private network and mgmt interface config system interface     edit "port1"         set ip 10.10.9.11 255.255.255.0         set allowaccess ping https ssh http fgfm     next     edit "port2"         set ip 15.15.15.102 255.255.255.0         set allowaccess ping https ssh http     next     edit "port3"         set ip 10.48.110.206 255.255.255.0         set allowaccess ping https ssh http end 2 . Configure the interface which is connected to intenet config system interface     edit "port3"         set ip 10.48.110.206 255.255.255.0         set allowaccess ping https ssh http end 3 . Set default rou

Difference between PPP and HDLC : ================================= 1 . Authentication : PPP supports the authentication and HDLC does not support the authentication 2 . Fragmentation Handling : PPP handles the fragmented packets in better way . Jitter can be controlled more effectively by PPP 3 . Compression Support : PPP supports the compression and HDLC does not support the compression 4 . Standard : PPP is OSI standard protocol and HDLC is cisco proprietary protocol 5 . Deployment : PPP is used in async dial up networks . eg PPPoE , PPPoA . So it is used in LAN HDLC is used in point to point serial links. It is used in WAN Difference between L3 switch and Router : ========================================= 1 . Switching speed : L3 Switch does the hardware switching using ASIC . So it is faster . Router does the software switching using microprocessors and device drivers

Telecom Testing Openings : Requirement : EMS/NMS testing . Domain Knowledge : L2/L3 , switches , routers preferable Experience : 3+ years Job Location : Chennai This is an urgent requirement Requirement : L2/L3 testing Domain knowledge : L2/L3 protocols with TCL , EXPECT Experience : 3+ years Job Location : Bangalore Please send your resume to mkvsenthilkumar@gmail.com

Virtual circuit Connection Verification (VCCV) : ================================================== VCCV provides connection verification services such as ping ,mpls ping regardless of underlying protocol such as MPLS ,IP tunnel. A network operator may use this to test the liveliness of the network. Ping and other IP messages are encapsulated using the PWE3 encapsulation .These messages are referred to as VCCV messages.VCCV messages are exchanged after negotiation between PEs. MPLS as PSN : ------------- VCCV creates control channel between PWE3 PES to exchange the IP monitoring tools. For more details of this , please refer PWE3 architecture.Packets sent across this channel are IP Packets ,allowing maximum flexibility. When control word is present on VC , it is possible to indicate the control channel by setting the control channel header . this is referred as inband MPLS VCCV as the control channel would be in band. When the control header is not in use , use of MPLS router alert la

L2TP is a protocol that is used to tunnel PPP over public network using IP.L2TP allows the encapsulation of any layer 3 protocol in its packets .The reason is tunnelling is done at layer 2 irrespective of layer 3 protocol. How L2TP provides security Like GRE , L2TP depends IPSec or any application layer mechanism to provide the type of security. Devices in L2TP session : ========================= PC , L2TP access concentrator (LAC),L2TP network server (LNS) The PC establishes a connection to a server known as LAC using dial up , POTS and DSL .The LAC initiates L2TP session to LNS .Typically authentication,authorization and accounting of the end user are done on the LNS itself using AAA server or local database. In running L2TP over IP backbone , UDP is used as carrier of all L2TP traffic which includes the control traffic of session between LAC and LNS. The initiator of tunnel (LAC) uses UDP port 1701. Types of L2TP tunnels : ======================== 1 . Compulsory tunnell

Fragmentation and GRE tunnels : =================================== What is Tunnel : A tunnel is logical interface that provides a way to encapsulate passenger packet inside a transport protocol. Tunneling has three memory components . 1 . Passenger protocol (Apple talk , CLNS,IP or IPX,DECNET) 2 . Carrier protocol – one of the encapsulation protocols GRE ,IP in IP tunnels 3. Transport protocol – The protocol used to carry the encapsulated protocol Original Packet : IP-TCP-Telnet Tunnel Encapsulated packet : IP-GRE-Original packet Where IP is transport protocol , GRE is the encapsulation protocol , IP is passenger protocol Example : Where IP and DECNET are passenger protocols and GRE is carrier protocol. Why tunnelling is required here ? Two non IP discontiguous networks are separated by IP network. The administrator may not want to connect them together by configuring DECNET in the IP ne