diff -X exclude_files -Nabur ospfd1.26/src/nbrfsm.C ospfd1.27/src/nbrfsm.C
--- ospfd1.26/src/nbrfsm.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/nbrfsm.C	Wed Feb 28 12:51:09 2001
@@ -224,6 +224,7 @@
 
     // Maintain count of adjacencies that we are
     // currently attempting
+    ap->adj_change(this, n_ostate);
     tap = n_ifp->transit_area();
     // now Full
     if (n_state == NBS_FULL) {
@@ -241,7 +242,6 @@
 	ospf->n_dbx_nbrs++;
     // Never go from Full state immed back into dbxchng
     else if (n_ostate == NBS_FULL) {
-        (void) n_ifp->more_adjacencies_needed(id(), true);
 	if (n_ifp->if_nfull-- == 1)
 	    n_ifp->reorig_all_grplsas();
 	if (tap && tap->n_VLs-- == 1)
@@ -249,7 +249,6 @@
 	ap->rl_orig();
     }
     else if (n_state <= NBS_2WAY && n_ostate >= NBS_EXST) {
-        (void) n_ifp->more_adjacencies_needed(id(), true);
 	exit_dbxchg();
 	if (n_ostate > NBS_EXST)
 	    ospf->n_dbx_nbrs--;
@@ -259,17 +258,11 @@
     if (n_ifp->state() == IFS_DR)
 	n_ifp->nl_orig(false);
 
-    /* If necessary, run Interface state machine with event
-     * NeighborChange
-     * Also, schedule routing calculation if we are
-     * limiting point-to-point adjacencies
-     */
+    // If necessary, run Interface state machine with event
+    // NeighborChange
     if ((n_state >= NBS_2WAY && n_ostate < NBS_2WAY) ||
-	(n_state < NBS_2WAY && n_ostate >= NBS_2WAY)) {
+	(n_state < NBS_2WAY && n_ostate >= NBS_2WAY))
 	n_ifp->run_fsm(IFE_NCHG);
-	if (ospf->PPAdjLimit != 0 && n_ifp->type() == IFT_PP)
-	    ospf->full_sched = true;
-    }
 }
 
 
@@ -286,7 +279,7 @@
     n_state = NBS_2WAY;
     if (!n_ifp->adjacency_wanted(this))
 	DelPendAdj();
-    else if (!n_ifp->more_adjacencies_needed(id(), false))
+    else if (!n_ifp->more_adjacencies_needed(id()))
 	DelPendAdj();
     else if (ospf->n_lcl_inits < ospf->max_dds) {
 	n_state = NBS_EXST;
diff -X exclude_files -Nabur ospfd1.26/src/ospf.h ospfd1.27/src/ospf.h
--- ospfd1.26/src/ospf.h	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/ospf.h	Wed Feb 28 12:51:09 2001
@@ -265,7 +265,7 @@
     // Version numbers
     enum {
 	vmajor = 1,	// Major version number
-	vminor = 26,	// Minor version number
+	vminor = 27,	// Minor version number
     };
 
     // Entry points into the OSPF code
diff -X exclude_files -Nabur ospfd1.26/src/rtrlsa.C ospfd1.27/src/rtrlsa.C
--- ospfd1.26/src/rtrlsa.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/rtrlsa.C	Wed Feb 28 12:51:09 2001
@@ -110,15 +110,27 @@
     SpfNbr *np;
 
     if ((np = if_nlst) && np->state() == NBS_FULL) {
+	PPAdjAggr *adjaggr;
+	uns16 adv_cost;
+	adv_cost = if_cost;
+	adjaggr = (PPAdjAggr *)if_area->AdjAggr.find(np->id(), 0);
+	if (adjaggr && adjaggr->first_full) {
+	    if (adjaggr->first_full != this)
+	        goto adv_stub;
+	    adv_cost = adjaggr->nbr_cost;
+	}
 	rlp->link_id = hton32(np->id());
 	rlp->link_data = hton32(unnumbered() ? if_IfIndex : if_addr);
 	rlp->link_type = LT_PP;
 	rlp->n_tos = 0;
-	rlp->metric = hton16(if_cost);
+	rlp->metric = hton16(adv_cost);
 	if_area->add_to_ifmap(this);
 	rlp++;
 	rtrhdr->nlinks++;
     }
+
+  adv_stub: // Advertise stub link to neighbor's IP address
+
     if (state() == IFS_PP && !unnumbered() && np) {
 	rlp->link_id = hton32(np->addr());
 	rlp->link_data = hton32(0xffffffffL);
diff -X exclude_files -Nabur ospfd1.26/src/spfarea.C ospfd1.27/src/spfarea.C
--- ospfd1.26/src/spfarea.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfarea.C	Wed Feb 28 12:51:09 2001
@@ -25,6 +25,7 @@
 #include "ospfinc.h"
 #include "ifcfsm.h"
 #include "system.h"
+#include "nbrfsm.h"
 
 /* Constructor for an OSPF area.
  */
@@ -620,3 +621,127 @@
 	    sl_orig(range->r_rte);
     }
 }
+
+/* Initialize the aggregate adjacency information to a given
+ * neighbor.
+ */
+
+PPAdjAggr::PPAdjAggr(rtid_t n_id) : AVLitem(n_id, 0)
+
+{
+    nbr_cost = 0;
+    first_full = 0;
+    nbr_mpath = 0;
+    n_adjs = 0;
+}
+
+/* The state of one of the conversations with a neighbor
+ * has changed. If this is a point-to-point link, and we
+ * are limiting the number of adjacencies, we may now have
+ * to take one ore more of the following actions:
+ * a) attempt to establish additional adjacencies
+ * b) re-originate our router-LSA
+ * c) rerun our routing calculation.
+ *
+ * If OSPF::PPAdjLimit is non-zero, we limit the number
+ * of point-to-point links which will become adjacent
+ * to a particular neighbor. If the "enlist" parameter
+ * is true, and there are insufficient adjacencies, we
+ * add all the 2-Way point-to-point interfaces to the
+ * pending adjacency list, since we don't know which
+ * ones we will be able to advance.
+ */
+
+
+void SpfArea::adj_change(SpfNbr *xnp, int n_ostate)
+
+{
+    bool more_needed;
+    PPAdjAggr *adjaggr;
+    IfcIterator iter(this);
+    SpfIfc *ip;
+    rtid_t n_id=xnp->id();
+    int n_state=xnp->state();
+    bool rescan=false;
+    uns16 old_cost;
+    SpfIfc *old_first;
+    MPath *old_mpath;
+
+    if (xnp->ifc()->type() != IFT_PP)
+        return;
+    if (ospf->PPAdjLimit == 0)
+        return;
+    // If necessary, allocate adjacency bookkeeping class
+    if (!(adjaggr = (PPAdjAggr *)AdjAggr.find(n_id, 0))) {
+        adjaggr = new PPAdjAggr(n_id);
+	AdjAggr.add(adjaggr);
+    }
+    /* Update number of current adjacencies, and determine
+     * whether a complete rescan is necessary.
+     */
+    if (n_state <= NBS_2WAY && n_ostate >= NBS_EXST)
+        adjaggr->n_adjs--;
+    else if (n_ostate <= NBS_2WAY && n_state >= NBS_EXST)
+        adjaggr->n_adjs++;
+    if ((n_state >= NBS_2WAY && n_ostate < NBS_2WAY) ||
+	(n_state < NBS_2WAY && n_ostate >= NBS_2WAY) ||
+	(n_ostate == NBS_FULL || n_state == NBS_FULL))
+        rescan = true;
+
+    // End with higher router ID will decide
+    more_needed = (ospf->my_id() >n_id) && (adjaggr->n_adjs< ospf->PPAdjLimit);
+    // Rescan only on relevant changes
+    if (!rescan && !more_needed)
+        return;
+    // Remember old parameters
+    old_cost = adjaggr->nbr_cost;
+    old_first = adjaggr->first_full;
+    old_mpath = adjaggr->nbr_mpath;
+    // Reset parameters before scan
+    adjaggr->nbr_cost = 0;
+    adjaggr->first_full = 0;
+    adjaggr->nbr_mpath = 0;
+    /* Find first adjacency, best bidirectional
+     * link cost, and calculate the multipath entry
+     * of those interfaces having the best cost.
+     * Also, modify list of pending adjacencies depending
+     * upon whether more are needed.
+     */
+    while ((ip = iter.get_next())) {
+        SpfNbr *np;
+        if (ip->type() != IFT_PP)
+	    continue;
+	if (!(np = ip->if_nlst))
+	    continue;
+	// To this same neighbor?
+	if (np->id() != n_id)
+	    continue;
+	if (np->state() == NBS_FULL && adjaggr->first_full == 0)
+	    adjaggr->first_full = ip;
+	if (np->state() == NBS_2WAY) {
+	    if (!more_needed)
+	        np->DelPendAdj();
+	    else
+	        np->AddPendAdj();
+	}
+	if (np->state() >= NBS_2WAY) {
+	    if (adjaggr->nbr_cost == 0 || adjaggr->nbr_cost > ip->cost()) {
+	        adjaggr->nbr_cost = ip->cost();
+		adjaggr->nbr_mpath = 0;
+	    }
+	    if (adjaggr->nbr_cost == ip->cost()) {
+		MPath *add_nh;
+		add_nh = MPath::create(ip, np->addr());
+		adjaggr->nbr_mpath = MPath::merge(adjaggr->nbr_mpath, add_nh);
+	    }
+	}
+    }
+    // Need to re-originate router-LSA?
+    if (adjaggr->nbr_cost != old_cost || adjaggr->first_full != old_first)
+        rl_orig();
+    // Need to rerun routing calculation?
+    if (adjaggr->nbr_mpath != old_mpath)
+        ospf->full_sched = true;
+}
+
+
diff -X exclude_files -Nabur ospfd1.26/src/spfarea.h ospfd1.27/src/spfarea.h
--- ospfd1.26/src/spfarea.h	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfarea.h	Wed Feb 28 12:51:09 2001
@@ -57,6 +57,7 @@
     int mospf_in_count; // Number of same;
 
     AVLtree abr_tbl;	// RTRrte's for area border routers
+    AVLtree AdjAggr;	// Aggregate adjacency information
 
   public:
     bool a_stub; 	// Options supported by area
@@ -107,6 +108,7 @@
     void add_to_ifmap(SpfIfc *ip);
     void delete_from_ifmap(SpfIfc *ip);
     InAddr id_to_addr(rtid_t id);
+    void adj_change(SpfNbr *, int n_ostate);
 
     // MOSPF routines
     void mospf_path_calc(InAddr, INrte *, int &, uns32 &, LsaList *);
@@ -121,6 +123,7 @@
     friend class IfcIterator;
     friend class AreaIterator;
     friend class SpfIfc;
+    friend class PPIfc;
     friend class DRIfc;
     friend class VLIfc;
     friend class SpfNbr;
@@ -198,3 +201,35 @@
 
     friend class SpfArea;
 };
+
+/* Data structure which collects all the information
+ * regarding point-to-point adjacencies to a particular node through
+ * this area. This is used to limit the number of
+ * point-to-point adjacencies, while still preserving
+ * forwarding semantics.
+ * Organized in SpfArea:AdjAggr by neighbor Router ID.
+ * - PPAdjAggr::nbr_cost is the smallest cost of any of the
+ * bidirectional links to the neighbor.
+ * - PPAdjAggr::first_full is one of the full adjacencies to the
+ * neighbor, and is used to trigger inclusion of the point-to-point
+ * link in the router-LSA.
+ * - PPAdjAggr::nbr_mpath is the collection of all the least cost
+ * bidirectional links to the neighbor, pre-calculated for use by
+ * the routing calculation.
+ * - PPAdjAggr::n_adjs is the number of neighbor relationships in state
+ * exstart or greater. This is limited by OSPF::PPAdjLimit.
+ */
+
+class PPAdjAggr : public AVLitem {
+    uns16 nbr_cost;	// Best cost to neighbor
+    SpfIfc *first_full;
+    MPath *nbr_mpath;
+    uns32 n_adjs;
+  public:
+    PPAdjAggr(rtid_t n_id);
+    friend class SpfArea;
+    friend class SpfIfc;
+    friend class SpfNbr;
+    friend class PPIfc;
+};
+
diff -X exclude_files -Nabur ospfd1.26/src/spfcalc.C ospfd1.27/src/spfcalc.C
--- ospfd1.26/src/spfcalc.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfcalc.C	Wed Feb 28 12:51:09 2001
@@ -886,31 +886,14 @@
 
 {
     rtid_t nbr_id;
-    IfcIterator iter(if_area);
-    SpfIfc *ip;
+    PPAdjAggr *adjaggr;
 
     nbr_id = dst->ls_id();
     if (ospf->PPAdjLimit == 0)
         return(new_nh);
-    while ((ip = iter.get_next())) {
-        SpfNbr *np;
-	if (ip == this)
-	    continue;
-        if (ip->type() != IFT_PP)
-	    continue;
-	if (!(np = ip->if_nlst))
-	    continue;
-	// To this same neighbor?
-	if (np->id() != nbr_id)
-	    continue;
-	if (np->n_state == NBS_2WAY) {
-	    InAddr t_gw;
-	    MPath *add_nh;
-	    t_gw = dst->ospf_find_gw(if_area->mylsa, ip->net(), ip->mask());
-	    add_nh = MPath::create(ip, t_gw);
-	    new_nh = MPath::merge(new_nh, add_nh);
-	}
-    }
-
+    else if (!(adjaggr = (PPAdjAggr *)if_area->AdjAggr.find(nbr_id, 0)))
+        return(new_nh);
+    else if (!adjaggr->nbr_mpath)
     return(new_nh);
+    return (adjaggr->nbr_mpath);
 }
diff -X exclude_files -Nabur ospfd1.26/src/spfhello.C ospfd1.27/src/spfhello.C
--- ospfd1.26/src/spfhello.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfhello.C	Wed Feb 28 12:51:10 2001
@@ -188,7 +188,7 @@
 	hlopkt->hlo_opts |= SPO_DC;
     hlopkt->hlo_pri = ospf->host_mode ? 0: if_drpri;
     hlopkt->hlo_dint = hton32(if_dint);
-    hlopkt->hlo_dr = hton32(if_dr);
+    hlopkt->hlo_dr = ((type() != IFT_PP) ? hton32(if_dr) : hton32(mtu));
     hlopkt->hlo_bdr = hton32(if_bdr);
     // Advance data pointer
     pkt->dptr = (byte *) (hlopkt + 1);
@@ -236,6 +236,15 @@
 	return;
     if (if_area->a_stub != ((hlopkt->hlo_opts & SPO_EXT) == 0))
 	return;
+    if (ospf->PPAdjLimit != 0 &&
+	type() == IFT_PP && ntoh32(hlopkt->hlo_dr) > mtu) {
+        if (ospf->spflog(LOG_BADMTU, 5)) {
+	    ospf->log(this);
+	    ospf->log("remote mtu ");
+	    ospf->log(ntoh32(hlopkt->hlo_dr));
+	}
+	return;
+    }
 
     // Find the neighbor structure
     // If one is not found, it is created
diff -X exclude_files -Nabur ospfd1.26/src/spfifc.C ospfd1.27/src/spfifc.C
--- ospfd1.26/src/spfifc.C	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfifc.C	Wed Feb 28 12:51:10 2001
@@ -1053,50 +1053,26 @@
  * ones we will be able to advance.
  */
 
-bool SpfIfc::more_adjacencies_needed(rtid_t, bool enlist)
+bool SpfIfc::more_adjacencies_needed(rtid_t)
 
 {
     return(true);
 }
 
-bool VLIfc::more_adjacencies_needed(rtid_t, bool enlist)
+bool VLIfc::more_adjacencies_needed(rtid_t)
 
 {
     return(true);
 }
 
-bool PPIfc::more_adjacencies_needed(rtid_t nbr_id, bool enlist)
+bool PPIfc::more_adjacencies_needed(rtid_t nbr_id)
 
 {
-    IfcIterator iter(if_area);
-    int n_adj;
-    bool more_needed=true;
-    SpfIfc *ip;
+    PPAdjAggr *adjaggr;
 
     if (ospf->PPAdjLimit == 0)
         return(true);
-    // End with higher router ID will decide
-    if (nbr_id  > ospf->my_id())
-        return(false);
-    for (n_adj = 0; more_needed && (ip = iter.get_next()); ) {
-        SpfNbr *np;
-        if (ip->type() != IFT_PP)
-	    continue;
-	if (!(np = ip->if_nlst))
-	    continue;
-	// To this same neighbor?
-	if (np->id() != nbr_id)
-	    continue;
-	if (np->n_state >= NBS_EXST) {
-	    n_adj++;
-	    more_needed = (n_adj < (int) ospf->PPAdjLimit);
-	}
-	else if (np->n_state == NBS_2WAY) {
-	    if (!more_needed)
-	        np->DelPendAdj();
-	    else if (enlist)
-	        np->AddPendAdj();
-	}
-    }
-    return(more_needed);
+    if (!(adjaggr = (PPAdjAggr *)if_area->AdjAggr.find(nbr_id, 0)))
+        return(true);
+    return ((ospf->my_id() >nbr_id) && (adjaggr->n_adjs< ospf->PPAdjLimit));
 }
diff -X exclude_files -Nabur ospfd1.26/src/spfifc.h ospfd1.27/src/spfifc.h
--- ospfd1.26/src/spfifc.h	Wed Feb 14 15:35:14 2001
+++ ospfd1.27/src/spfifc.h	Wed Feb 28 12:51:10 2001
@@ -228,7 +228,7 @@
     virtual void restart_hellos();
     virtual void stop_hellos();
     virtual bool elects_dr();
-    virtual bool more_adjacencies_needed(rtid_t, bool enlist);
+    virtual bool more_adjacencies_needed(rtid_t);
     virtual MPath *add_parallel_links(MPath *, TNode *);
 
     friend class PhyInt;
@@ -324,7 +324,7 @@
     virtual RtrLink *rl_insert(RTRhdr *, RtrLink *);
     virtual int rl_size();
     virtual void add_adj_to_cand(class PriQ &cand);
-    virtual bool more_adjacencies_needed(rtid_t, bool enlist);
+    virtual bool more_adjacencies_needed(rtid_t);
     virtual MPath *add_parallel_links(MPath *, TNode *);
 };
 
@@ -349,7 +349,7 @@
     virtual RtrLink *rl_insert(RTRhdr *, RtrLink *);
     void update(class RTRrte *endpt);
     friend class OSPF;
-    virtual bool more_adjacencies_needed(rtid_t, bool enlist);
+    virtual bool more_adjacencies_needed(rtid_t);
     virtual MPath *add_parallel_links(MPath *, TNode *);
 };
 

.