diff --git a/src/components/cl/hier/alltoall/alltoall.c b/src/components/cl/hier/alltoall/alltoall.c
index 0048474c98..f2f602e6aa 100644
--- a/src/components/cl/hier/alltoall/alltoall.c
+++ b/src/components/cl/hier/alltoall/alltoall.c
@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * Copyright (c) 2022-2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
  *
  * See file LICENSE for terms.
  */
@@ -13,7 +13,7 @@ ucc_base_coll_alg_info_t
             {.id   = UCC_CL_HIER_ALLTOALL_ALG_NODE_SPLIT,
              .name = "node_split",
              .desc = "splitting alltoall into two concurrent a2av calls"
-                     " withing the node and outside of it"},
+                     " within the node and outside of it"},
         [UCC_CL_HIER_ALLTOALL_ALG_LAST] = {
             .id = 0, .name = NULL, .desc = NULL}};
 
@@ -23,10 +23,12 @@ UCC_CL_HIER_PROFILE_FUNC(ucc_status_t, ucc_cl_hier_alltoall_init,
                          ucc_coll_task_t **task)
 {
     ucc_cl_hier_team_t     *cl_team = ucc_derived_of(team, ucc_cl_hier_team_t);
+    ucc_rank_t              tsize   = UCC_CL_TEAM_SIZE(cl_team);
+    uint64_t               *counts, *displs;
     ucc_status_t            status;
     ucc_base_coll_args_t    args;
-    int                     i, count;
-    ucc_rank_t              team_size;
+    int                     i;
+    size_t                  count;
     ucc_mc_buffer_header_t *h;
 
     if (UCC_IS_INPLACE(coll_args->args)) {
@@ -45,42 +47,43 @@ UCC_CL_HIER_PROFILE_FUNC(ucc_status_t, ucc_cl_hier_alltoall_init,
         args.args.mask  = UCC_COLL_ARGS_FIELD_FLAGS;
         args.args.flags = 0;
     }
-    args.args.flags |= UCC_COLL_ARGS_FLAG_CONTIG_SRC_BUFFER |
-                       UCC_COLL_ARGS_FLAG_CONTIG_DST_BUFFER;
-    team_size = UCC_CL_TEAM_SIZE(cl_team);
 
-    status =
-        ucc_mc_alloc(&h, sizeof(int) * team_size * 2, UCC_MEMORY_TYPE_HOST);
+    args.args.flags |= UCC_COLL_ARGS_FLAG_CONTIG_SRC_BUFFER |
+                       UCC_COLL_ARGS_FLAG_CONTIG_DST_BUFFER |
+                       UCC_COLL_ARGS_FLAG_COUNT_64BIT |
+                       UCC_COLL_ARGS_FLAG_DISPLACEMENTS_64BIT;
+    status = ucc_mc_alloc(&h, sizeof(uint64_t) * tsize * 2,
+                          UCC_MEMORY_TYPE_HOST);
     if (ucc_unlikely(UCC_OK != status)) {
         cl_error(team->context->lib,
                  "failed to allocate %zd bytes for full counts",
-                 sizeof(int) * team_size * 2);
+                 sizeof(uint64_t) * tsize * 2);
         return status;
     }
 
-    args.args.src.info_v.buffer   = coll_args->args.src.info.buffer;
-    args.args.dst.info_v.buffer   = coll_args->args.dst.info.buffer;
-    args.args.src.info_v.datatype = coll_args->args.src.info.datatype;
-    args.args.dst.info_v.datatype = coll_args->args.dst.info.datatype;
-    args.args.src.info_v.mem_type = coll_args->args.src.info.mem_type;
-    args.args.dst.info_v.mem_type = coll_args->args.dst.info.mem_type;
-
-    args.args.src.info_v.counts = h->addr;
-    args.args.src.info_v.displacements =
-        PTR_OFFSET(h->addr, sizeof(int) * team_size);
-
+    args.args.src.info_v.buffer        = coll_args->args.src.info.buffer;
+    args.args.dst.info_v.buffer        = coll_args->args.dst.info.buffer;
+    args.args.src.info_v.datatype      = coll_args->args.src.info.datatype;
+    args.args.dst.info_v.datatype      = coll_args->args.dst.info.datatype;
+    args.args.src.info_v.mem_type      = coll_args->args.src.info.mem_type;
+    args.args.dst.info_v.mem_type      = coll_args->args.dst.info.mem_type;
+    args.args.src.info_v.counts        = h->addr;
+    args.args.src.info_v.displacements = PTR_OFFSET(h->addr,
+                                         sizeof(uint64_t) * tsize);
     args.args.dst.info_v.counts        = args.args.src.info_v.counts;
     args.args.dst.info_v.displacements = args.args.src.info_v.displacements;
 
-    count = (int)coll_args->args.src.info.count / team_size;
-    ((int *)args.args.src.info_v.counts)[0]        = count;
-    ((int *)args.args.src.info_v.displacements)[0] = 0;
+    counts = (uint64_t *)args.args.src.info_v.counts;
+    displs = (uint64_t *)args.args.src.info_v.displacements;
 
-    for (i = 1; i < team_size; i++) {
-        ((int *)args.args.src.info_v.counts)[i] = count;
-        ((int *)args.args.src.info_v.displacements)[i] =
-            ((int *)args.args.src.info_v.displacements)[i - 1] + count;
+    count     = coll_args->args.src.info.count / tsize;
+    counts[0] = count;
+    displs[0] = 0;
+    for (i = 1; i < tsize; i++) {
+        counts[i] = count;
+        displs[i] = displs[i - 1] + count;
     }
+
     status = ucc_cl_hier_alltoallv_init(&args, team, task);
     if (UCC_OK != status) {
         cl_error(team->context->lib, "failed to init split node a2av task");