Catalyst 4500-X Fixed 10 GE Aggregation Switch
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
PAGP<br />
1. IF Standby loses contact with Active, it assumes Active peer has<br />
failed, and so it transitions to Active state.<br />
• Now there are “dual actives.”<br />
2. The new Active sends out new active switch ID over the trusted<br />
MEC in PAgP frames.<br />
• (ePAgP uses TLV to carry new Active SW ID)<br />
Si<br />
Si<br />
3. Original Active switch sees new active sw-id on MEC and begins<br />
Dual Active Recovery operations on itself:<br />
• All non-VSL interfaces are error-disabled<br />
• It waits in “recovery mode” until the VSL is operational.<br />
• Once VSL is recovered, former Active reloads, boots into<br />
Standby mode, and the formerly error-disabled ports are reenabled<br />
after bootup.<br />
If the VSL fails, the standby sends<br />
PAgP with TLV containing (new) Active<br />
<strong>Switch</strong> ID. Original Active reacts by<br />
error-disabling all non-VSL ports.<br />
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 61
Change language