{"id":833,"date":"2021-08-20T03:08:46","date_gmt":"2021-08-20T03:08:46","guid":{"rendered":"http:\/\/feralpacket.org\/?p=833"},"modified":"2021-08-20T03:08:46","modified_gmt":"2021-08-20T03:08:46","slug":"rapid-stp-rstp-notes","status":"publish","type":"post","link":"https:\/\/feralpacket.org\/?p=833","title":{"rendered":"Rapid STP (RSTP) Notes"},"content":{"rendered":"

Rapid STP (RSTP)<\/span><\/p>\n

 – 802.1W<\/p>\n

 – STP plus fast convergence features<\/p>\n

<\/p>\n

 – No forward-delay or max-age-time<\/p>\n

     -> Theoretical reconvergence time is up to 6 seconds<\/p>\n

New Port Types<\/span><\/p>\n

 – Access ports \u2014> Edge port<\/p>\n

 – Trunk port \u2014> Point-to-Point port<\/p>\n

 – Switch to Hub \u2014> Shared port<\/p>\n

 – Multiple connections to a Hub \u2014> All ports except one will become Backup ports<\/p>\n

     -> Backup ports are ports that receive our own BPDUs<\/p>\n

<\/p>\n

Failover does not have to wait for reconvergence<\/p>\n

<\/p>\n

Proposal<\/span><\/p>\n

 – Please make this port a root port<\/p>\n

 – Receiving switch<\/p>\n

     -> Disconnect from rest of topology<\/p>\n

     -> Decide<\/p>\n

     -> Send agreement<\/p>\n

     -> Make port a root port<\/p>\n

     -> Reconnect to the rest of topology<\/p>\n

 – Disagreement<\/p>\n

     -> Both switches don\u2019t want to change port to a root port<\/p>\n

 – The root bridge never sends an agreement<\/p>\n

Proposal and Agreement Procedure<\/span><\/p>\n

     1.  In RSTP once the root bridge is elected, it sends a Proposal message out all designated ports<\/p>\n

     2.  The Proposal is a request to make the receiving port a root port<\/p>\n

     3.  Whenever a switch receives a Proposal, it disconnects itself from the rest of the topology to decide to agree or disagree<\/p>\n

     4.  If agree, an Agreement message is sent back and the sending port becomes a root port<\/p>\n

     5.  Once the root port is decided, the switch sends Proposal messages further out potential designated ports<\/p>\n

Configuring RSTP<\/span><\/p>\n

SW1(config)#  spanning-tree mode rapid-pvst<\/span><\/p>\n

Convergence Methods<\/span><\/p>\n

 – Only two<\/p>\n

     -> STP <\/p>\n

          -> Slower<\/p>\n

     -> RSTP<\/p>\n

          -> Faster<\/p>\n

          -> Used by MST for convergence<\/p>\n

Topological Design<\/span><\/p>\n

  – STP to VLAN mapping<\/p>\n

     -> Common Spanning Tree (CST)<\/p>\n

     -> Per-VLAN Spanning Tree (PVST)<\/p>\n

     -> Per-VLAN Spanning Tree + (PVST+)<\/p>\n

     -> Multiple Spanning Tree (MST)<\/p>\n

Common Spanning Tree (CST)<\/span><\/p>\n

 – One STP instance for all VLANs<\/p>\n

 – Only one root election<\/p>\n

 – Limited to 100 VLANs<\/p>\n

 – No load balancing between links or switches<\/p>\n

 – Only supports dot1q<\/p>\n

 – Only supports STP for convergence<\/p>\n

<\/p>\n

Per-VLAN Spanning Tree (PVST)<\/span><\/p>\n

 – One STP instance per VLAN<\/p>\n

 – 100 VLANs means<\/p>\n

     -> 100 STP instances<\/p>\n

     -> 100 root bridges<\/p>\n

     -> 100 BPDUs<\/p>\n

 – Only supports ISL<\/p>\n

 – Only supports STP for convergence<\/p>\n

<\/p>\n

Per-VLAN Spanning Tree + (PVST+)<\/span><\/p>\n

 – Supports both ISL and dot1q<\/p>\n

 – Supports both STP and RSTP for convergence<\/p>\n","protected":false},"excerpt":{"rendered":"

Rapid STP (RSTP)<\/p>\n","protected":false},"author":1,"featured_media":828,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[31,61,15],"class_list":["post-833","post","type-post","status-publish","format-standard","hentry","category-ccie","tag-published","tag-spanning-tree","tag-stp"],"_links":{"self":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=833"}],"version-history":[{"count":1,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/833\/revisions"}],"predecessor-version":[{"id":971,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/posts\/833\/revisions\/971"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=\/wp\/v2\/media\/828"}],"wp:attachment":[{"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/feralpacket.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}