https://ttl-expired.net/tags/quick-reference/ Recent content in Quick-Reference on TTL Expired Hugo en-us Tue, 30 Jun 2026 00:00:00 +0000 https://ttl-expired.net/juniper-study-guides/jncis_sp_quick_reference/ Tue, 30 Jun 2026 00:00:00 +0000 https://ttl-expired.net/juniper-study-guides/jncis_sp_quick_reference/ <h2 id="ospf">OSPF</h2> <h3 id="ospf-packet-types">OSPF Packet Types</h3> <table> <thead> <tr> <th>Type</th> <th>Name</th> <th>Purpose</th> </tr> </thead> <tbody> <tr> <td>1</td> <td>Hello</td> <td>Neighbor discovery, DR/BDR election, keepalive</td> </tr> <tr> <td>2</td> <td>DBD</td> <td>LSDB table of contents exchange</td> </tr> <tr> <td>3</td> <td>LSR</td> <td>Request specific missing LSAs</td> </tr> <tr> <td>4</td> <td>LSU</td> <td>Delivers actual LSAs</td> </tr> <tr> <td>5</td> <td>LSAck</td> <td>Confirms LSU receipt</td> </tr> </tbody> </table> <h3 id="lsa-types">LSA Types</h3> <table> <thead> <tr> <th>Type</th> <th>Name</th> <th>Originated By</th> <th>Scope</th> <th>Blocked By</th> </tr> </thead> <tbody> <tr> <td>1</td> <td>Router</td> <td>Every router</td> <td>Area</td> <td>—</td> </tr> <tr> <td>2</td> <td>Network</td> <td>DR</td> <td>Area</td> <td>—</td> </tr> <tr> <td>3</td> <td>Summary</td> <td>ABR</td> <td>Domain</td> <td>Totally Stubby, Totally NSSA</td> </tr> <tr> <td>4</td> <td>ASBR Summary</td> <td>ABR</td> <td>Domain</td> <td>Totally Stubby, Totally NSSA, NSSA, Stub</td> </tr> <tr> <td>5</td> <td>AS-External</td> <td>ASBR</td> <td>Domain</td> <td>All stub and NSSA areas</td> </tr> <tr> <td>7</td> <td>NSSA External</td> <td>ASBR (NSSA)</td> <td>NSSA only</td> <td>— (translated to Type 5 at ABR)</td> </tr> </tbody> </table> <h3 id="area-types">Area Types</h3> <table> <thead> <tr> <th>Area</th> <th>Type 3</th> <th>Type 4</th> <th>Type 5</th> <th>Type 7</th> <th>Default Route</th> </tr> </thead> <tbody> <tr> <td>Standard</td> <td>Yes</td> <td>Yes</td> <td>Yes</td> <td>No</td> <td>No</td> </tr> <tr> <td>Backbone</td> <td>Yes</td> <td>Yes</td> <td>Yes</td> <td>No</td> <td>No</td> </tr> <tr> <td>Stub</td> <td>Yes</td> <td>No</td> <td>No</td> <td>No</td> <td>Yes (auto)</td> </tr> <tr> <td>Totally Stubby</td> <td>No</td> <td>No</td> <td>No</td> <td>No</td> <td>Yes (auto)</td> </tr> <tr> <td>NSSA</td> <td>Yes</td> <td>No</td> <td>No</td> <td>Yes</td> <td>No (configurable)</td> </tr> <tr> <td>Totally NSSA</td> <td>No</td> <td>No</td> <td>No</td> <td>Yes</td> <td>Yes (auto)</td> </tr> </tbody> </table> <h3 id="adjacency-states">Adjacency States</h3> <p>Down → Init → 2-Way → ExStart → Exchange → Loading → <strong>Full</strong></p>