Spanning-Tree Procotol
 802.1D

Rapid STP (RSTP)
 802.1W

Multiple-instance STP (MSTP)
 802.1S
 - pre kazdu VLANku mame jeden STP strom

BPDU - packety/ramce pre STP
BID  - Bridge ID (cislo switchu)
     - dve casti:
       2B - Priorita switchu (4b - Priorita, 12b-VLANID) - preto v ktokoch po 4096)
       6B - MAC adresa back-plane
     - cim nizsie, tym vyssia priorita 
Root bridge - switch s minimalnym BID
Designated bridge - switch, kt ma pre dane medium odblokovany port
Root port - port, kt sa da dostat ku root switchu (up-stream)
Designated port - port ku designated switchu
Blocking port - zablokovane switchovanie
Root path cost - cena ku root switchu

Porovnavanie BPDU:
 - Root BID
 - Root Path Cost
 - Sender BID
 - Port priority
 - Port index

Stavy portov:
 - Disabled
 - Blocking (neprenasa data a ani neposiela BPDU)
20s
 - Listening (podobne ako blocking, len sa predpoklada, ze co ak tento port sa otvori)
15s
 - Learning (zacina sa switch ucit MAC adresy, ale data nejdu (BPDU uz idu))
15s
 - Forwarding (vsetko fici ako ma :))

50 sekund total

Nastavenia BPDU:
 - Hello timer   - 2s
 - Max_age       - 20s (ako dlho som ochotny tolerovat, ze mi chybaju BPDU od suseda)
 - Forward Delay - 15s (ako dlho trva predhoc z Listening na Learning a z Learning na Forwarding)

Na root porty neposielame BPDU.


Zmeny v topologii

ID document 12013
 - switch, kt to zisti posle prazdne BPDU s priznakom TCN (topology change notify) cez root-port
 - nadradeny switch potvrdi prijatie cez BPDU (s priznakom TCA - topology change ackowledge)
 - toto BPDU sa dostane az ku root-switchu
 - root-switch posle spat BPDU s priznakom TC (topology change) (toto sa posiela max_age + forward delay 35s)
 - vsetky switche co dostanu toto BPDU nastavia MAC zaznamy na forward delay 


****************
Monitorovanie trafficu

odkial          --> monitor session 1 source interface fastEthernet 0/24
kde to posielat --> monitor session 1 destination interface gigabitEthernet 0/24


RSTP

Alternativny port - zaloha root portu
Backup port - zaloha designated portu

RSTP Cisco document 24062


Konfiguracia:

Zapina sa pomocou: spanning-tree mode rapid-pvst
Nove otestovanie STP na portoch clear span dete

MSTP
 - ma regiony
 - region je definovany cez:
  - meno
  - revizia
  - mapovanie VLAN na tzv instancie

- v regione su M-tree (instancie v oblaciku)
- IST (cislo isntancie 0) - strom, kt trci navonok z oblacika

Konfiguracia:
 spanning-t mst config
  meno MENO
  revision CISLO
  instance CISLO vlan VLANKY

Cisco document -> 24248


Port-channels

- bud na pevno to nastavime alebo automaticky (PAgP - stary protokol (Cisco), LACP
(IEEE) - novy protokol)

Automaticke:
 - interface ...
 - channel-group 1 mode ...


EOF