- Last Updated: Monday, 08 October 2018 20:27
What is Precision Time Protocol (PTP) ?
Precision Time Protocol (P2P) is a new feature of Packet Tracer 7.0 available in IE2000 industrial switches.
This time synchronization protocol is defined in IEEE-1588 as Precision Clock Synchronization for Networked Measurements and Control Systems, and was developed to synchronize the clocks in networks devices that include distributed device clocks with various levels of precision and stability. Acurate time synchronization is vital for smart grid power automation applications such as virtual power generators and peak-hour billing, but also for network outage monitoring tools which require a high level of time accuracy and stability.
PTP configuration in Packet Tracer 7.0
Precision Time protocol can be simulated in Packet Tracer 7.0 using IE2000 switches. These switches features PTP boundary, end-to-end transparent, and forward modes.
Switch(config)#ptp mode ?
boundary Boundary Clock mode
e2etransparent End-to-End Transparent Clock mode
forward Forward packets without processing
Configure PTP using the following commands and verify the configuration using the show ptp clock and show ptp port IOS command :
Switch(config)#ptp mode boundary
Switch(config)#interface fastEthernet 1/1
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- Last Updated: Sunday, 13 January 2019 10:19
Introduction - IPSEC VPN on ISR routers
Cisco Packet Tracer allows IPSEC VPN configuration between routers. The example below presents a basic VPN configuration over a Frame Relay between Paris and New-York using Cisco 2811 routers.
IPSEC Tunneling allows network adminisrators to use the Internet to create secure connections between networks (teleworkers, remote sites, ...). Cisco 2811 routers use the ISAKMP and IPsec tunneling standards to crete and manage tunnels. IPsec provides authentication (AH) and encryption (ESP) services to prevent unauthorized data access or modification. ISAKMP is the negotiation protocol that makes peers negociate on how to build the IPsec security association.
A major problem with IPSec sessions is that they do not support multicast or broadcast traffic. Enabling dynamic routing protocols such as OSPF or EIGRP requires multicast or brodcast support to allow hellos and updates traffic between routers.
Solution : Build another generic tunnel over IPSEC. Three options available in Cisco routers :
- Virtual Tunnel Interface (VTI)
- Generic Routing Encapsulation (GRE)
- DMVPN and GET VPN
Good news : GRE over IPSEC has been working in Packet Tracer since at least version 6.0.1 . This tunnel design allows OSPF dynamic routing over the tunnel
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