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go to page: <- 1 2 single page| Corso GNU/Linux Avanzato '09 | Fri, 29 May 09 |
| Per il corso Netstudent avanzato, organizzato dall'associazione NetStudent presso il Politecnico di Torino, ho illustrato (in troppo poco tempo) le caratteristiche principali del sistema operativo FreeBSD, con esempi dal vivo dei comandi e delle procedure. Le slide utilizzate sono qui disponibili (sorgenti ODP). | |
| Corso GNU/Linux base '09 pt2 | Fri, 20 Mar 09 |
| Continua il corso GNU/Linux base organizzato dall'associazione NetStudent presso il Politecnico di Torino. Riporto le slide utilizzate nella settimana lezione, argomenti trattati: rete, networking dalle basi ai servizi, samba suite in modo descrittivo. I sorgenti sono qui disponibili. | |
| Corso GNU/Linux base '09 | Sun, 15 Feb 09 |
| Anche quest'anno con l'associazione NetStudent abbiamo proposto il corso GNU/Linux base presso il Politecnico di Torino. Riporto le slide utilizzate nella seconda e terza lezione, versione rivista ed ampliata sui comandi di base, filesystem, permessi. I sorgenti sono qui disponibili. | |
| Cisco routers and multicast | Fri, 23 Jan 09 |
| Here I report some useful commands to manage and debug multicast traffic and routing using Cisco IOS network devices. In the configuration used for samples, I have 2 routers with two interfaces each one: the local one on Fa0/0 and the WAN over witch one there's a tunnel Tu0. But those commands are valid every time you need to manage multicast. mrinfo A command that shows the neighbours multicast routers. In the end you find kind of transport to reach the neighbour. cisco# mrinfo 192.168.1.254 [version 12.4] [flags: PMA]: 10.1.1.2 -> 10.1.1.1 [1/0/tunnel/pim] 192.168.1.254 -> 0.0.0.0 [1/0/pim/querier/leaf] mstat -source IP- -destination IP- -multicast group- Show a trace route of multicast packet with statistics. You can define source and destination address, as well as the multicast group to use: cisco#mstat 192.168.1.254 192.168.0.254 224.1.2.3
Type escape sequence to abort.
Mtrace from 192.168.1.254 to 192.168.0.254 via group 224.1.2.3
From source (?) to destination (?)
Waiting to accumulate statistics......
Results after 10 seconds:
Source Response Dest Packet Statistics For Only For Traffic
192.168.1.254 192.168.1.254 All Multicast Traffic From 192.168.1.254
| __/ rtt 52 ms Lost/Sent = Pct Rate To 224.1.2.3
v / hop -42 s --------------------- --------------------
192.168.1.254
10.1.1.2 ? Prune sent upstream
| ^ ttl 0
v | hop 0 ms -1/0 = --% 0 pps 0/0 = --% 0 pps
10.1.1.1 ? Reached RP/Core
| \__ ttl 1
v \ hop 42 s 0 0 pps 0 0 pps
192.168.0.254 192.168.1.254
Receiver Query Source
show ip mroute Shows the multicast routing table. The table is usually dynamic, so pay attention and look at timeout values. cisco#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.1.2.3), 2d00h/stopped, RP 10.1.1.1, flags: SJCF
Incoming interface: Tunnel0, RPF nbr 10.1.1.1
Outgoing interface list:
FastEthernet0/0, Forward/Sparse-Dense, 2d00h/00:02:53
(192.168.1.254, 224.1.2.3), 00:01:15/00:02:07, flags: PFT
Incoming interface: FastEthernet0/0, RPF nbr 0.0.0.0
Outgoing interface list: Null
(*, 224.0.1.40), 2d00h/00:02:00, RP 10.1.1.1, flags: SJCL
Incoming interface: Tunnel0, RPF nbr 10.1.1.1
Outgoing interface list:
FastEthernet0/0, Forward/Sparse-Dense, 2d00h/00:02:00
show ip mroute active Like before, but shows only currently transmitting multicast traffic passing through a multicast route in the router. At default, the source shown must generate at least 4kbps. cisco#show ip mroute active
Active IP Multicast Sources - sending >= 4 kbps
a negative (-) Rate counts pps being fast-dropped
Group: 224.1.2.3, (?)
Source: 192.168.1.1 (?)
Rate: 19 pps/18 kbps(1sec), 9 kbps(last 20 secs), 14 kbps(life avg)
show ip igmp groups To show IGMP groups present on the router and expiry times cisco#show ip igmp groups IGMP Connected Group Membership Group Address Interface Uptime Expires Last Reporter Group Accounted 224.1.2.3 FastEthernet0/0 2d00h 00:02:12 192.168.1.1 224.0.1.40 FastEthernet0/0 2d00h 00:02:19 192.168.1.254 The next three commands are useful to debug Protocol Indipendent Multicast (PIM), usually used as a multicast routing protocol (another one more generic is NHRP). show ip pim interface To show interfaces involved with PIM packet protocol, with source address and destination route cisco#show ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.1.1.2 Tunnel0 v2/SD 1 30 1 0.0.0.0
192.168.1.254 FastEthernet0/0 v2/SD 0 30 1 192.168.1.254
show ip pim neighbor To show the ip address of neighbor PIM-enabled routers with interface connected to, and expiry times cisco#show ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
S - State Refresh Capable
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.1.1.1 Tunnel0 1d23h/00:01:34 v2 1 / B S
show ip pim rp mapping Shows mapping between PIM group and Rendez-vous Point, eg. the IP interface of the router where you reach the multicast group. cisco#show ip pim rp mapping
PIM Group-to-RP Mappings
Group(s): 224.0.0.0/4, Static
RP: 10.1.1.1 (?)
| |
| Wikipedia offline | Dec 2007 |
| Ho rilasciato il testo della mia tesi di laurea specialistica sotto licenza CC-BY-NC. Il titolo completo e` Sviluppo di un ambiente software per la consultazione offline di Wikipedia. E` disponibile il pdf completo e le slides annesse La tesi verte sui metodi per ottenere una versione offline multipiattaforma di Wikipedia utilizzando software opensource; in particolare e` stato definito un meccanismo di conversione e un'interfaccia per la consultazione offline, incluso un motore di ricerca ECMAscript. Il sistema prodotto puo` essere memorizzato su diversi supporti (dvdrom, pendrive, etc) e accessibili da molti sistemi operativi senza richiedere dipendenze particolari. Il processo e` applicabile a qualsiasi versione di Wikipedia e con poche modifiche a qualsiasi installazione di MediaWiki. Per motivi di responsabilita` in Italia l'utilizzo del software deve essere personale. Il nome in codice del progetto e` "WaNDA", acronimo di WaNDA ancora Non Definitivamente Aggiornata. Gli applicativi prodotti sono situati su Sourceforge con il nome di WaNDA-tools: e` qui disponibile l'ultima versione del pacchetto. | |
| GNU/Linux | Nov 2007 |
| Slides per il corso base GNU/Linux Netstudent. Terza lezione: shell, comandi base, struttura del filesystem, permessi. corsobaselinux_3_nov07.pdf (source) | |
| FLOSS | Sep 2007 |
| Slides on Free/Libre/Open-Source Software, in italian: FLOSSeCO.pdf (source) | |
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