diff --git a/code/include/swoc/IPSrv.h b/code/include/swoc/IPSrv.h
index de2f5e8..d4f245b 100644
--- a/code/include/swoc/IPSrv.h
+++ b/code/include/swoc/IPSrv.h
@@ -85,29 +85,29 @@ class IP4Srv {
    */
   bool load(swoc::TextView text);
 
-  /** Change the address.
+  /** Assign an IPv4 address.
    *
    * @param addr Address to assign.
    * @return @a this
    */
   self_type &assign(IP4Addr const &addr);
 
-  /** Change the host_order_port.
+  /** Assign a port.
    *
-   * @param port Port to assign.
+   * @param port Port to assign (host order)
    * @return @a this.
    */
   self_type &assign(in_port_t port);
 
-  /** Change the address and port.
+  /** Assign an address and port.
    *
    * @param addr Address to assign.
-   * @param port Port to assign.
+   * @param port Port to assign (host order).
    * @return @a this
    */
   self_type &assign(IP4Addr const &addr, in_port_t port);
 
-  /** Change the address and port.
+  /** Assign an address and port from an IPv4 socket address.
    *
    * @param s A socket address.
    * @return @a this
@@ -116,7 +116,7 @@ class IP4Srv {
 
 protected:
   IP4Addr _addr;       ///< Address.
-  in_port_t _port = 0; ///< Port.
+  in_port_t _port = 0; ///< Port [host order].
 };
 
 /// An IPv6 address and host_order_port, modeled on an SRV type for DNS.
@@ -193,17 +193,17 @@ class IP6Srv {
    */
   self_type &assign(IP6Addr const &addr);
 
-  /** Change the host_order_port.
+  /** Assign a port.
    *
-   * @param port Port to assign.
+   * @param port Port [host order].
    * @return @a this.
    */
   self_type &assign(in_port_t port);
 
-  /** Change the address and host_order_port.
+  /** Assign an address and port.
    *
-   * @param addr Address to assign.
-   * @param port Port to assign.
+   * @param addr Address.
+   * @param port Port [host order].
    * @return @a this
    */
   self_type &assign(IP6Addr const &addr, in_port_t port);
@@ -217,7 +217,7 @@ class IP6Srv {
 
 protected:
   IP6Addr _addr;       ///< Address.
-  in_port_t _port = 0; ///< Port.
+  in_port_t _port = 0; ///< Port [host order]
 };
 
 /// An IP address and host_order_port, modeled on an SRV type for DNS.
@@ -228,11 +228,17 @@ class IPSrv {
 public:
   IPSrv() = default; ///< Default constructor.
   explicit IPSrv(IP4Addr addr, in_port_t port = 0) : _srv(IP4Srv{addr, port}), _family(addr.family()) {}
+  /// Construct for IPv6 address and port.
   explicit IPSrv(IP6Addr addr, in_port_t port = 0) : _srv(IP6Srv{addr, port}), _family(addr.family()) {}
+  /// Construct from generic address and port.
   explicit IPSrv(IPAddr addr, in_port_t port = 0);
+  /// Construct from socket address.
   explicit IPSrv(sockaddr const *sa);
+  /// Construct IPv4 service from socket address.
   explicit IPSrv(sockaddr_in const *s);
+  /// Construct IPv6 service from socket address.
   explicit IPSrv(sockaddr_in6 const *s);
+  /// Construct from Endpoint.
   explicit IPSrv(IPEndpoint const &ep);
 
   /** Construct from a string.
@@ -259,21 +265,17 @@ class IPSrv {
   /// @return The protocol of the current value.
   constexpr sa_family_t family() const;
 
+  /// @return @c true if this is a valid service, @c false if not.
+  bool is_valid() const;
   /// @return @c true if the data is IPv4, @c false if not.
   bool is_ip4() const;
   /// @return @c true if hte data is IPv6, @c false if not.
   bool is_ip6() const;
 
   /// @return The IPv4 data.
-  IP4Srv const &
-  ip4() const {
-    return _srv._ip4;
-  }
+  IP4Srv const & ip4() const;
   /// @return The IPv6 data.
-  IP6Srv const &
-  ip6() const {
-    return _srv._ip6;
-  }
+  IP6Srv const & ip6() const;
 
   /** Change the address.
    *
@@ -289,88 +291,91 @@ class IPSrv {
    */
   self_type &assign(IP6Addr const &addr);
 
-  /** Change the address.
+  /** Assign an address.
    *
-   * @param addr Address to assign.
+   * @param addr Address.
    * @return @a this
    *
-   * If @a addr isn't valid then no assignment is made.
+   * If @a addr isn't valid then no assignment is made, otherwise the family is changed to that of
+   * @a addr.
    */
   self_type &assign(IPAddr const &addr);
 
-  /** Change the host_order_port.
+  /** Assign port.
    *
-   * @param port Port in host order.
+   * @param port Port [host order].
    * @return @a this.
    */
   self_type &assign(in_port_t port);
 
-  /** Change the address and port.
+  /** Assign an IPv4 address and port.
    *
-   * @param addr Address to assign.
-   * @param port Port to assign.
+   * @param addr Address.
+   * @param port Port [host order].
    * @return @a this
    */
   self_type &assign(IP4Addr const &addr, in_port_t port);
 
-  /** Change the address and port.
+  /** Assign an IPv6 address and port.
    *
-   * @param addr Address to assign.
-   * @param port Port to assign.
+   * @param addr Address.
+   * @param port Port [host order].
    * @return @a this
    */
   self_type &assign(IP6Addr const &addr, in_port_t port);
 
-  /** Change the address and port.
+  /** Assogm address amd [prt/
    *
    * @param sa Socket address.
    * @return @a this
+   *
+   * The assignment is ignored if @a sa is not a valid IP family, otherwise the family is changed
+   * to that of @a sa.
    */
   self_type &assign(sockaddr const *sa);
 
-  /** Change the address and port.
+  /** Assign an IPv4 address and port.
    *
    * @param s Socket address.
    * @return @a this
    */
   self_type &assign(sockaddr_in const *s);
 
-  /** Change the address and port.
+  /** Assign an IPv6 address and port.
    *
    * @param s Socket address.
    * @return @a this
    */
   self_type &assign(sockaddr_in6 const *s);
 
-  /** Change the address and host_order_port.
+  /** Assign an address and port.
    *
-   * @param addr Address to assign.
-   * @param port Port to assign.
+   * @param addr Address.
+   * @param port Port [host order].
    * @return @a this
    *
-   * If @a addr isn't valid then no assignment is made.
+   * If @a addr isn't valid then no assignment is made, otherwise the family is changed to match
+   * @a addr.
    */
   self_type &assign(IPAddr const &addr, in_port_t port);
 
+  /// Copy assignment.
   self_type &operator=(self_type const &that) = default;
+  /// Assign from IPv4.
   self_type &operator=(IP4Srv const &that);
+  /// Assign from IPv6.
   self_type &operator=(IP6Srv const &that);
-  self_type &
-  operator=(sockaddr const *sa) {
-    return this->assign(sa);
-  }
-  self_type &
-  operator=(sockaddr_in const *s) {
-    return this->assign(s);
-  }
-  self_type &
-  operator=(sockaddr_in6 const *s) {
-    return this->assign(s);
-  }
+  /// Assign from generic socket address.
+  self_type & operator=(sockaddr const *sa);
+  /// Assign from IPv4 socket address.
+  self_type & operator=(sockaddr_in const *s);
+  /// Assign from IPv6 socket address.
+  self_type & operator=(sockaddr_in6 const *s);
 
 protected:
   /// Family specialized data.
   union data {
+    std::monostate _nil; ///< Nil / invalid state.
     IP4Srv _ip4; ///< IPv4 address (host)
     IP6Srv _ip6; ///< IPv6 address (host)
 
@@ -555,19 +560,42 @@ inline IPAddr
 IPSrv::addr() const {
   return _srv.addr(_family);
 }
+
 inline constexpr sa_family_t
 IPSrv::family() const {
   return _family;
 }
+
+inline bool IPSrv::is_valid() const { return AF_INET == _family || AF_INET6 == _family; }
+
 inline bool
 IPSrv::is_ip4() const {
   return _family == AF_INET;
 }
+
 inline bool
 IPSrv::is_ip6() const {
   return _family == AF_INET6;
 }
 
+inline IP4Srv const& IPSrv::ip4() const {
+  return _srv._ip4;
+}
+
+inline IP6Srv const& IPSrv::ip6() const {
+  return _srv._ip6;
+}
+
+inline constexpr in_port_t
+IPSrv::host_order_port() const {
+  return _srv.port(_family);
+}
+
+inline in_port_t
+IPSrv::network_order_port() const {
+  return ntohs(_srv.port(_family));
+}
+
 inline auto
 IPSrv::assign(IP6Addr const &addr) -> self_type & {
   _srv._ip6.assign(addr, this->host_order_port());
@@ -656,14 +684,16 @@ IPSrv::assign(sockaddr_in6 const *s) -> self_type & {
   return *this;
 }
 
-inline constexpr in_port_t
-IPSrv::host_order_port() const {
-  return _srv.port(_family);
+inline IPSrv::self_type & IPSrv::operator=(sockaddr const *sa) {
+  return this->assign(sa);
 }
 
-inline in_port_t
-IPSrv::network_order_port() const {
-  return ntohs(_srv.port(_family));
+inline IPSrv::self_type & IPSrv::operator=(sockaddr_in const *s) {
+  return this->assign(s);
+}
+
+inline IPSrv::self_type & IPSrv::operator=(sockaddr_in6 const *s) {
+  return this->assign(s);
 }
 
 inline IPAddr
@@ -675,6 +705,7 @@ constexpr inline in_port_t
 IPSrv::data::port(sa_family_t f) const {
   return (f == AF_INET) ? _ip4.host_order_port() : (f == AF_INET6) ? _ip6.host_order_port() : 0;
 }
+
 // --- Independent comparisons.
 
 inline bool
diff --git a/unit_tests/test_TextView.cc b/unit_tests/test_TextView.cc
index 2f13dfb..ebeb6c2 100644
--- a/unit_tests/test_TextView.cc
+++ b/unit_tests/test_TextView.cc
@@ -545,7 +545,7 @@ TEST_CASE("TextView Conversions", "[libswoc][TextView]") {
   x.assign("-9223372036854775809");
   CHECK(svtoi(x) == IMIN);
 
-  // floating point is never exact, so "good enough" is all that is measureable. This checks the
+  // floating point is never exact, so "good enough" is all that iisnts measureable. This checks the
   // value is within one epsilon (minimum change possible) of the compiler generated value.
   auto fcmp = [](double lhs, double rhs) {
     double tolerance = std::max({1.0, std::fabs(lhs), std::fabs(rhs)}) * std::numeric_limits<double>::epsilon();