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BigIron RX Series Configuration Guide
53-1001810-01
Convergence in a simple topology
13
NOTE
The rapid convergence will not occur on ports connected to shared media devices, such as hubs. To
take advantage of the rapid convergence provided by RSTP, make sure to explicitly configure all
point-to-point links in a topology.
Convergence at start up
In
Figure 53
, two bridges Switch 2 and Switch 3 are powered up. There are point-to-point
connections between Port3/Switch 2 and Port3/Switch 3.
FIGURE 53
Convergence between two bridges
At power up, all ports on Switch 2 and Switch 3 assume Designated port roles and are at discarding
states before they receive any RST BPDU.
Port3/Switch 2, with a Designated role, transmits an RST BPDU with a proposal flag to
Port3/Switch 3. A ports with a Designated role sends the proposal flag in its RST BPDU when they
are ready to move to a forwarding state.
Port3/Switch 3, which starts with a role of Designated port, receives the RST BPDU and finds that it
is superior to what it can transmit; therefore, Port3/Switch 3 assumes a new port role, that of a
Root port. Port3/Switch 3 transmits an RST BPDU with an agreed flag back to Switch 2 and
immediately goes into a forwarding state.
Port3/Switch 2 receives the RST BPDU from Port3/Switch 3 and immediately goes into a
forwarding state.
Now RSTP has fully converged between the two bridges, with Port3/Switch 3 as an operational root
port in forwarding state and Port3/Switch 2 as an operational Designated port in forwarding state.
Port3
Designated
port
Port3
Root port
Bridge priority = 1500
Routing Switch 2
Routing Switch 3
Bridge priority = 2000
Summary of Contents for Brocade DCX
Page 40: ...xl BigIron RX Series Configuration Guide 53 1001810 01 ...
Page 72: ...lxxii BigIron RX Series Configuration Guide 53 1001810 01 ...
Page 88: ...16 BigIron RX Series Configuration Guide 53 1001810 01 Searching and filtering output 1 ...
Page 300: ...228 BigIron RX Series Configuration Guide 53 1001810 01 Displaying IP information 7 ...
Page 318: ...246 BigIron RX Series Configuration Guide 53 1001810 01 Deploying a LAG 8 ...
Page 418: ...346 BigIron RX Series Configuration Guide 53 1001810 01 SuperSpan 12 ...
Page 482: ...410 BigIron RX Series Configuration Guide 53 1001810 01 MRP CLI example 14 ...
Page 506: ...434 BigIron RX Series Configuration Guide 53 1001810 01 Displaying VSRP information 15 ...
Page 582: ...510 BigIron RX Series Configuration Guide 53 1001810 01 Viewing Layer 2 ACLs 20 ...
Page 634: ...562 BigIron RX Series Configuration Guide 53 1001810 01 Troubleshooting ACLs 21 ...
Page 642: ...570 BigIron RX Series Configuration Guide 53 1001810 01 Trunk formation 22 ...
Page 746: ...674 BigIron RX Series Configuration Guide 53 1001810 01 Displaying RIP filters 24 ...
Page 808: ...736 BigIron RX Series Configuration Guide 53 1001810 01 Displaying OSPF information 25 ...
Page 938: ...866 BigIron RX Series Configuration Guide 53 1001810 01 Displaying MBGP information 27 ...
Page 950: ...878 BigIron RX Series Configuration Guide 53 1001810 01 Using secure copy 28 ...
Page 988: ...916 BigIron RX Series Configuration Guide 53 1001810 01 Clearing IS IS information 29 ...
Page 1054: ...982 BigIron RX Series Configuration Guide 53 1001810 01 Sample 802 1x configurations 33 ...
Page 1108: ...1036 BigIron RX Series Configuration Guide 53 1001810 01 sFlow 39 ...
Page 1190: ...1118 BigIron RX Series Configuration Guide 53 1001810 01 Displaying RIPng information 44 ...
Page 1270: ...1198 BigIron RX Series Configuration Guide 53 1001810 01 Displaying ACLs 47 ...
Page 1310: ...1238 BigIron RX Series Configuration Guide 53 1001810 01 Displaying OSPFv3 information 48 ...
Page 1382: ...1310 BigIron RX Series Configuration Guide 53 1001810 01 Commands That Require a Reload D ...
Page 1435: ...BigIron RX Series Configuration Guide 1363 53 1001810 01 VSRP E ...
Page 1436: ...1364 BigIron RX Series Configuration Guide 53 1001810 01 VSRP E ...