Poster

PTP IEEE1588-2008 accuracy and test

The accuracy of the PTP IEEE1588-2008 on the SAS7210-T MPLS router is shown in figures below.

Depending on the stability of the GM (General Master Clock) , the accuracy of clock recovery by the PTP protocol is 10^-9 to 10^-10 .

 

BGP konfiguracja na przykładzie routera 7750SR

Configuration DHCP local server in router 7750SR

MVR multicast protocol layer 2

Multicast VLAN Registration protocol in Cisco switches deliver multicast packets received from a source VLAN to destination VLAN. Multicast routing has to be disabled when MVR is enabled. Multicast traffic can be delivered to the source VLAN by a port. This port can be work in trunk or access mode. Multicast traffic will be received from destination VLAN by a port or ports. These ports have to works in access mode only. These ports call subscribers ports.
When we want to configure MVR in a switch we have to configure in global configuration and in subscribers ports.
In the global configuration, we set up source VLAN and a  multicast group which will be transferred do the destination VLAN to the subscriber’s ports.

mvr vlan 611
mvr
mvr querytime 10
mvr mode dynamic
mvr group 232.0.2.10
mvr group 232.40.10.8
mvr group 239.40.10.8

In subscriber’s ports are configured multicast groups which we needed receive.

interface FastEthernet0/24
 switchport access vlan 621
 switchport mode access
 mvr type receiver
 mvr vlan 611 group 232.0.2.10
 mvr vlan 611 group 232.40.10.8
 mvr vlan 611 group 239.40.10.8
 mvr immediate
Parallel to the MVR protocol can work properly IGMP protocol.

ip igmp snooping vlan 621 static 0100.5e00.020a interface Fa0/24
ip igmp snooping vlan 621 static 0100.5e28.0a08 interface Fa0/24

or

ip igmp snooping vlan 621 static 232.0.2.10 interface Fa0/24
ip igmp snooping vlan 621 static 232.40.10.8 interface Fa0/24
ip igmp snooping vlan 621 static 239.40.10.8 interface Fa0/24

 

 

Multicast routing pim sparse mode in Cisco routers – example

When we want to configure multicast routing pim sparse mode in Cisco router please read this example.
First, we have to run multicast routing.

ip multicast-routing

Protocol ip pim sparse mode works properly only when exists rendezvous point (RP). We have to create rendezvous point in the router. In this case, we create a loopback interface for example:

interface Loopback1
ip address 1.2.3.4   255.255.255.255
ip pim sparse-mode

Next, we have to connect rendezvous point with the loopback address.

ip pim rp-address 1.2.3.4

We to assume that VLAN 500 will be input VLAN and VLAN 600 will be output.
We have to create properly interface VLAN like below:

interface VLAN 500
ip address 10.50.10.252 255.255.255.0
ip pim sparse-mode

interface VLAN 600
ip address 10.60.10.252 255.255.255.0
ip pim sparse-mode
ip igmp static-group 239.0.2.10

The last line informs router that selected multicast group is carried from VLAN 500 to VLAN 600.

Finally, we have to switch on IGMP SNOOPING on selected interface for selected multicast group in output VLAN like below:

ip igmp snooping vlan 600 static 0100.5e00.020a interface Gi1/9 – same routers to

require mac address for the multicast group

or for other routers, the command line is:

ip igmp snooping vlan 600 static 239.0.2.10 interface Gi1/9

Acoustic spectra for radio signal DAB and FM

Measurement of Spectra a signal using a Fast Fourier Transform FFT in the domain of time are performed in a finite time. In other words, the measured are portions of a waveform of the signal of the specified length. Fragments extracted cyclically subjected are to the FFT. Fragments the waveform on shores contains discontinuities because are collected at intervals. Discontinuities cause blurring to spectra. The spectra of the downloaded portions of the waveform are different from the spectra of the whole continuous the signal subjected to measurement. To reduce blur spectra signal is passed the signal through a time window. The Time window reduced spillage of energy in the domain of frequency. Measurements were made for spectra of acoustic signals DAB and FM. The signal was passed through a time window. Used were of the time window: Rectangular, Bartlett, Hanning, Hamming, Blackman, Blackman-Harris, Flat-Top. The time window it is function shaping the signal measured undergone FFT. In the domain of time, signal is as function of time and was multiplying with function describing by the time window. In the domain of frequency occurs weave these functions. The result of the signal is subjected to FFT.

 

See articles :     http://sp9mco.com/articles/

Acoustic spectra DAB and FM